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The Unix Crash Course - How to Example Code

1. The correct way to see what s in your Short Films direc tory then would be s Movies Short Films Note how the backslash just before the space means This is just a space keep it moving folks Of course if you have to enter a lot of text with spaces it d be a real pain to type the backslash before every single one Fortunately instead of using backslashes you can enclose the whole mess with single quotation marks That is instead of typing this cd Users chris My Documents Letters to finish Letter to Craig doc you could just type this cd Users chris My Documents Letters to finish Letter to Craig doc It can get even more complicated For example what if there s a single quote in the path Answer Protect it with double quotes Ah but you have years of study ahead of you grasshoppa MAC OS X THE MISSING MANUAL Control E Moves the insertion point to the end of the line Control T Transposes the previous two characters Esc F Moves the insertion point to the beginning of the next word Esc B Moves the insertion point to the beginning of the current word Esc Delete Erases the previous word defined as anything that ends with a space slash or most other punctuation marks periods and asterisks not included You have to hold down Esc as you press Delete repeat for each word Esc D Erases the word or section of a word following the insertion point Esc C Capitali
2. Special keys The bash shell offers dozens of special keystroke shortcuts for navigation You may recognize many of them as useful undocumented shortcuts that work in any Cocoa application but even more are available and useful in Terminal Keystroke Effect Control U Erases the entire command line you re working on to the insertion point s left Control A Moves the insertion point to the beginning of the line UP TO SPEED No Spaces Allowed Terminal doesn t see a space as a space It thinks that a space means for example I ve just typed a command and what follows is an argument If you want to see what s in your Short Films directory therefore don t bother typing Is Movies Short Films You ll only get a No such file or directory error message thanks to the space in the Short Films directory name Similarly symbols like and amp have special meanings in Unix If you try to type one in a pathname because a directory name contains for example you ll have noth ing but trouble Fortunately you can work around this quirk by using a third reserved or special character the backslash It says Ignore the special meaning of the next character a space for example I m not using it for some special Unix meaning l m using the following space as well a space At a Unix user group meeting you might hear someone say Use the backslash character to escape the space character
3. Fortunately almost every Unix program comes with a help file It may not appear within an elegant gradient gray Lion window in fact it s pretty darned plain but it offers much more material than the regular Mac Help Center These user manual pages or manpages hold descriptions of virtually every command and program available Mac OS X in fact comes with manpages on almost 4 500 topics over 35 000 printed pages worth Alas manpages rarely have the clarity of writing or the learner focused approach of the Mac Help Center They re generally terse just the facts descriptions In fact youll probably find yourself needing to reread certain sections again and again The information they contain however is invaluable to new and experienced Unix fans alike and the effort spent mining them is usually worthwhile Using man To access the manpage for a given command type man followed by the name of the command youre researching For example to view the manpage for the Is command enter man Is Tip The k option flag lets you search by keyword For example man k applescript produces a list of all manpages that refer to AppleScript whereupon you can pick one of the names in the list and man that page name Now the manual appears one screen at a time as shown in Figure 7 A typical manpage begins with these sections Name The name and a brief definition of the command Synopsis Presents the syntax of the com
4. No it s not the code name of a top secret project Apple forgot to remove before shipping Lion X11 is another name for the X Window System a GUI that came to being on Unix systems at about the same time the Macintosh was introduced GUI stands for graphic user interface and it means icons windows and menus like you re used to not typing commands at a prompt many of the Unix GUI applications both free and commercial that have become available over the years More importantly X11 lets your Mac run 7 Getting X11 to work right with Mac OS X used to require some fiddling But in Lion you can run it without fuss X11 comes with several X programs which are found in ust X11 bin Your shell knows about this directory and Terminal knows about X11 so you can run these applications like any other command To launch the X11 clock for example start in Terminal Type xclock and press Return After a moment the X11 icon appears in your Dock and a small clock window appears beside your other windows just like any normal program As you ll discover X11 programs are more visually pleasing than Unix code But they have not ahem been designed by Apple s finest To stop the X application you can close its window or press Control C in Terminal No new prompt appears while the X application is running Many other X applications come with Lion in Terminal type s usr X7 1 bin to list them
5. aon chris mini B24 E Ga a 2 8 6 Mew Butter Eliza Have Issues with My Mother to someone about whatever is bothering you and MacOSX _ i ghrin mace Mindi is ready to listen an Ree Gn EH M A Hidden in the emacs text nania i editing program is a fully iss sssrmeis enseris sr ta unlicensed automated psycho 0 pan a RR aag ae iai analyst named Eliza To enter her office open Terminal type emacs and press Return After the introductory screen has appeared press Shift Esc type xdoctor and then press Return ee ee nii iL fete Pit e a Figure 12 A new nano session One key difference between nano and say TextEdit To scroll you must use the t and 4 keys or the Prev Page and Next Page commands not the Terminal scroll bar Therapy whether it s about your frustrations with your Mac I am the psychotherapist Eliza begins Please describe or any other subject is expensive Still it feels good to talk your problems Each time you are finished talking type RET twice She means Press the Return key twice As you can see from this illustration she isn t exactly Sigmund Freud But she s very entertaining and surprisingly responsive When your session is finished press Control X and then Con trol C to exit Eliza and emacs 44 MAC OS X THE MISSING MANUAL grep The grep program is a filter a powerful program designed to search data for text tha
6. THE UNIX CRASH COURSE Changing Permissions 33 Changing Permissions 34 So how do you solve the problem One solution would be to turn on the root account as described on page 671 and then log on as root But that s a hassle and turning on the root account always entails a security risk Instead you could open the Get Info window for the iChat application file make yourself the owner and then type in your name and password to prove youre an administrator Then open Terminal use the chmod command now that youre the file s owner return to the Finder open Get Info again and change the file s permis sions back to root For a Unix guru that s an awful lot of steps for something that should take only a few keystrokes As it turns out the final possibility is quick and easy which explains its popularity in Unix circles It s the sudo command sudo sudo is a cool command name Technically it s short for superuser do which means youre allowed to execute any command as though youd logged in with the root superuser account but without actually having to turn on the root account log out log back in again and so on It s also a great command name because it looks as though it would be pronounced pseudo as in I m just pretending to be the root user for a moment I m here under a pseudonym In fact you pronounce it SOO doo because it comes from superuser do In the privacy of your o
7. Weird and fun UP TO SPEED Your Metadata is Safe with Us Metadata means data about data For example the handwritten note on a shoebox of photos is metadata for the image data inside reminding you of the photos date location camera information or even which CDs hold the digital versions This metadata lets you locate and access the actual data quickly and also helps you decide if you should go to the trouble in the first place Computer files have metadata too and the more the computer can scribble down the easier it can operate with the bazillions of files living on your hard drive The Mac has always stored some file metadata in one way or another last modified date permissions and so on But these days it really goes whole hog It now recognizes a Unix feature called extended attributes to store all kinds of file metadata In fact many of the features described in this book like Time Machine and Downloaded Application Tagging depend on extended attributes to perform their magic Apple also uses extended attributes now to keep track of traditional Mac metadata like resource forks features carried over from OS 9 that Mac OS X still has to recognize When you create modify or move files in the Finder you don t have to worry about extended attributes the Mac always keeps them together with their associated files When you re working with files on the command line how ever you have to be more
8. in the same directory with different names Just remember to add a backslash before a space if you want to name the copy with two words Thesis Backup for example Tip f this command doesn t seem to work remember that you must type the full names of the files you re moving including their file name suffixes like doc or gif which Mac OS X usually hides Using the s com mand before a copy may help you find out what the correct full file names should be Or you may just want to use the Tab completion feature making Terminal type the whole name for you BONUS CHAPTER THE UNIX CRASH COURSE Navigating in Unix 15 Working with Files and Directories Copying and renaming To copy the same file into say your Documents folder instead just change the last phrase so that it specifies the path like this cp Reviews doc Documents Reviews2 doc Tip Note that cp replaces identically named files without warning Use the i flag that is cp if you want to be warned before cp replaces a file like this Copying without renaming To copy something into another directory without changing its name just use a pathname without a file name as the final phrase So to copy Reviews doc into your Documents folder for example you would type cp Reviews doc Documents Tip You can use the directory shortcut which stands for the current working directory to copy files from another directory into the wo
9. to make the same flip but also transform the file into a TIFF file enter this sips f vertical s format tiff TenLakes jpg out TenLakesFlipped tif FTP and SFTP FTP and its relative telnet aren t exclusively Unix programs of course Techies from all walks of operating system life have used telnet for years whenever they want to tap into another computer from afar and FTP to deliver and download software 20 Useful Unix Utilities UP TO SPEED Secrets of Virtual Memory The top command s table offers a fascinating look at the way Mac OS X manages memory In the VM section for example you ll see current statistics for pageins and pageouts that is how many times the virtual memory system has had to set down software code for a moment as it juggles your open programs in actual memory These numbers are pointed out in Figure 11 The pageins and pageouts statistics are composed of two different numbers like this 45457 0 pageins 42946 0 pageouts The bigger number tells you how many times your Mac has had to shuffle data in and out of memory since the Mac started up The number in parentheses indicates how much of this shuffling it s done within the past second The pageouts value is the number to worry about If it stays above zero for a while your Mac is gasping for RAM as the hard drive thrashing sounds and program switching delays are probably also telling you In the listing of individual progra
10. type man ps and hit Return BONUS CHAPTER THE UNIX CRASH COURSE 20 Useful Unix Utilities 39 20 Useful Unix Utilities 40 shutdown It s perfectly easy to shut down your Mac from the menu But using shutdown with its h flag for halt in Terminal has its advantages For one thing you can control when the shutdown occurs using one of these three options Now You can safely shut down by typing shutdown h now Actually only the root user is allowed to use shutdown so yowd really type sudo shutdown h now and then type in your administrator s password when asked Later today Specify a time instead of now Typing sudo shutdown h 2330 for example shuts down your machine at 11 30 p m today 2330 is military time notation for 11 30 p m Anytime in the next 100 years To make the machine shut down at 5 00 p m on December 9 2012 for example you could type sudo shutdown h 1212091700 That number code is in year last two digits month date hour minute format Tip Once you set the auto shutdown robot in motion you can t stop it easily You must use the kil command described earlier to terminate the shutdown process itself To find out shutdown s ID number in order to terminate it look for the pid number in the output of the shutdown command or use the top or ps command There are still more useful flags For example using the r flag instead of h means restart instead of just shutting
11. Tahoel moy Tahoez moy Finishedtoyies files The final clause indicates The files you want to copy where they go Where you want to put them Here s one more example a command that copies everything files and directories with Tahoe in its name into someone else s Drop Box directory cp R Tahoe miho Public Drop Box mv Moving and Renaming Files and Directories Now that you know how to copy files you may want to move or rename them To do so you use the Unix command mv almost exactly the same way you d use cp except that it always moves directories inside of directories yowre moving so you don t have to type R 16 OK I m really confused You say that slashes denote nested directories But also know that traditionally colons denote the Mac s internal folder notation and that s why can t use colons in the names of my icons What s the story The Mac s file system called HFS Plus uses colons as path separators instead of slashes Therefore in the Finder you are allowed to use slashes in file names but not colons Conversely in Terminal you can use colons in file names but not slashes Behind the scenes Mac OS X automatically converts one form of punctuation to the other as necessary For example a file named Letter 6 21 2012 in the Finder shows up as Letter 6 21 2012 in Terminal Likewise a directory named Attn Jon in Terminal appears with the name Attn Jon in the Finder
12. X THE MISSING MANUAL In other words it s an industrial strength assassin that accepts no pleas for mercy from the program you re killing If you check top and find out that BeeKeeper Pro s process ID is 753 yowd abort it by typing kill 753 and then pressing Return If it still appears to be breathing add the 9 flag like this kill 9 753 which should deliver the fatal blow You might even need to rerun the command until you receive output similar to kill 753 no such pid telling you that indeed that process is no more please hold your fire Tip f that s too much work another command killall does its dirty work using only the name of the process you want to off For example to kill Beekeeper Pro with killall enter killall Beekeeper Pro You can use the 9 flag with killall as well Be aware however that killall is not as discriminate as kill as its name implies it kills all instances of the application at least those that you have permission to eliminate So for example if someone else is logged in using Screen Sharing and also using BeeKeeper Pro killall if run as root kills that person s Beekeeper Pro session as well as your own open What operating system would be complete without a way to launch programs In Mac OS X s version of Unix the command is easy enough open a as in open a Chess The a flag allows you to specify an application by name regardless of where it is on your hard drive
13. also a w in the owner column that user root could in theory even make changes to the file although there would never be a reason to do so The three forms of access read write and execute have slightly different meanings when applied to files and directories BONUS CHAPTER THE UNIX CRASH COURSE 31 Changing Permissions 32 Read access to a file means someone can open and read it In the case of a program like iChat the system needs to read the file on your behalf in order to run it Read access to a directory folder on the other hand just means someone using Terminal can see a list of its contents using a command like Is Write access to a file means someone can modify and save changes to it Write access to a directory means someone can add remove and rename any item the folder contains but not necessarily the items within its subdirectories Note Turning off write access to a certain file doesn t protect it from deletion As long as write access is turned on for the folder it s in the file is still trashable To protect a certain file from deletion in other words you must also worry about the access settings of the folder that encloses it Execute access when applied to an application means people can run that par ticular program In fact Unix distinguishes applications from ordinary files by checking the status of this setting Of course you can t very well run
14. cr2 raw image You can find more about constructing your queries here http developer apple com mac library documentation Carbon Conceptual SpotlightQuery Concepts QueryFormat html launchd launchd is a multitalented Unix program responsible for launching system programs during startup or anytime thereafter Part of its job is triggering certain commands according to a specified schedule even when youre not logged in People can use launchd to trigger daily backups or monthly maintenance for example You can pro gram your unattended software robot by editing simple property list files Mac OS X comes set up to run launchd automatically it s the very first process that starts up when the Mac does It launches all your other startup items in fact If you open the Activity Monitor program in your Applications Utilities folder you ll see it listed among the administrator processes that your Mac is running all the time In fact launchd comes with three under the hood Unix maintenance tasks already scheduled a daily job a weekly job and a monthly job They come set to run at 3 15 a m the first two and 5 30 a m If your Mac isn t generally turned on in the middle of the night these healthy jobs run the next time it s awake But if youre feeling ambitious you can change the time for them to be run A glance at man launchd plist shows you how Hint It involves using sudo nano and editing the three com apple periodic
15. directory you want to switch to Want to see what s in the Movies directory of your home directory Type cd Users chris Movies and press Return The prompt shows you what it considers to be the directory you re in now the new working directory If you perform an ls command at this point Terminal shows you the contents of your Movies directory That s a lot of typing of course Fortunately instead of typing out that whole path the absolute path as it s called you can simply specify which directory you want to see relative to the directory youre already in For example if your Home folder is the working directory the relative pathname of the Trailers directory inside the Movies directory would be Movies Trailers That s a lot shorter than typing out the full absolute pathname Users chris Movies Trailers If your brain isn t already leaking from the stress here s a summary of the three dif ferent ways you could switch from your home directory to Movies cd Users chris Movies That s the long way the absolute pathname It works no matter what your working directory is cd Movies This too is an absolute pathname that you could type from anywhere It relies on the shorthand which means my home directory unless you follow the with another account name e cd Movies This streamlined relative path exploits the fact that youre already in your home directory Lion Watch Actually ther
16. down as in sudo shutdown r now One of the most powerful uses of shutdown is turning off Macs by remote control either from across the network or across the world via Internet That is you can use SSH described in Chapter 21 to issue this command tar gzip zip You know how Mac OS X can create compressed zip archive files Terminal lets you stuff and combine files in these formats with the greatest of ease To compress a file just type gzip a space and then the pathname of the file you want to compress or drag the file directly from the desktop into the Terminal window When you press Return Mac OS X compresses the file Tarring a folder combining its contents into a single file a tarball as Unix hepcats call it is only slightly more complicated You have to specify the resulting file s name followed by the actual directory pathname like this tar cf Memos tar Users chris Memos Add the z flag if you want to tar and compress the folder tar czf Memos tar gz Users chris Memos To combine and compress files using zip just specify a name for the zip file and the names of the items to zip like this zip StaffordLake zip Stafford which would cram all files in the working directory whose name begins with Stafford into a single archive To zip a folder include the r flag as well zip r Memos Users chris Memos MAC OS X THE MISSING MANUAL In any case if you switch to the Finder you see that t
17. exactly the way Spotlight does it You can even specify which document you want to open into that program like this open a Preview FunnyPhotoOfCasey tif Tip The e flag opens any text document in TextEdit or whatever your default text editor may be like this open e Diary txt This shortcut saves you from having to specify TextEdit itself The real utility of this command might not be apparent at first but imagine doing something like this in the Finder Select from a folder of hundreds of HTML files those that contain the word Sequoia in their file names and preview them all with the Firefox browser regardless of what application they re actually associated with You could do it with the help of the Spotlight command but that would take quite a few steps In Terminal though you just switch to that directory using the cd com mand and type open a Firefox Sequoia Done Of course you may not often bother simply launching programs and documents this way Nevertheless you can see how useful open can be when youre writing automated scripts for your Mac like those used by the launchd command scheduler program page 666 ps The ps process status command is another way to get a quick look at all the pro grams running on your Mac even the usually invisible ones complete with their ID numbers For the most helpful results use the e and f flags like this ps ef For a complete description of these and other flags
18. found himself with some spare time after his main project an operating system called Multics was canceled Bell Labs had withdrawn from the expensive project disappointed with the results after four years of work But Thompson still thought the project an OS that worked well as a cooperative software development environment was a promising idea Eventually he and colleague Dennis Ritchie came up with the OS that would soon be called Unix a pun on Multics Bell Labs saw the value of Unix agreed to support further development and became the first corporation to adopt it In the age when Thompson and Ritchie started their work on Unix most programmers wrote code that would work on only one kind of computer or even one computer model Unix however was one of the first portable operating sys tems its programs could run on different kinds of computers without having to be completely rewritten That s because Thompson and Ritchie wrote Unix using a new programming language of their own invention called C In a language like C programmers need only write their code once After that a software Cuisinart called a compiler can convert the newly hatched software into the form a particular computer model can understand Unix soon found its way into labs and thanks to AT amp T s low academic licensing fees universities around the world Programmers all over the world added to the source code fixed bugs and then passed those mo
19. grants you root pow ers without you actually having to og into the root account Details are on page 654 Using the sudo command is faster easier and more secure than using the root account It doesn t present the risk that you ll walk away from your Mac while logged in as the root user thereby opening yourself up to complete annihilation from a passing evildoer in person or over the Internet But if you re a Unix geek and you want to poke around the lowest levels of the operating system or you re in a time of crisis and you really really need to log in with the root account see the free downloadable appendix to this chapter Enabling the Root Account It s available on this book s Missing CD page at www missingmanuals com MAC OS X THE MISSING MANUAL BONUS CHAPTER THE UNIX CRASH COURSE 51 Putting It Together 52 Tip You don t have to type out that entire command line every time you need it you can save the whole thing as a command file on your desktop that runs when double clicked First create a new plain text document you can use TextEdit Type in the entire command you want to me morialize Save the document with a name ending with command for example Processimages command Documents with this extension appear with a spiffy icon in the Finder Next make that file itself executable by using the chmod command If for example you want only the owner of the Processimag
20. hugely important Mac OS X and Unix feature The behind the scenes permissions setting for a file or folder determines whether or not youre allowed to open it change it or delete it Permissions are the cornerstone of several important Mac OS X features including the separation of user accounts and the relative invulnerability of the operating system itself As you know from Chapter 12 you can get a good look at the permissions settings for any file folder or disk by highlighting it and choosing File Get Info in the Finder But even there youre not seeing all the permission settings Unix provides and every now and then you might want to Suppose for example that youre a teacher in charge of a computer lab containing 25 Macs On each computer you ve created Standard accounts see Chapter 12 for five students for a total of 125 student accounts MAC OS X THE MISSING MANUAL Soon after the students start using the lab you notice a bit more giggling and frantic typing than youd expect from students researching Depression era economics You nonchalantly stroll to the end of the room and do a quick about face at one of the desks Aha iChat Horribly depressed by the comments you read there regarding your fashion sense you vow to keep students from using that application ever again You have several options Delete iChat from the Applications folder Unfortunately the Computer Club meets in your classroom after school and its
21. into its subfolders or up into its parent folders In this chapter you ll be asked to specify a certain file or folder in this tree of folders But you can t see their icons from the command line So how are you supposed to identify the file or folder you want By typing its pathname The pathname is a string of folder names something like a map that takes you from the root so on The root level is for learning Unix purposes the rough equivalent of your main hard drive window It s represented in Unix by a single slash The phrase Users in other words means the Users folder in my hard drive window or in Unix terms the Users directory at the root level One way to refer to the Documents folder in your own Home folder for example would be Users chris Documents if your name is Chris that is MAC OS X THE MISSING MANUAL This time try typing cal 4 2012 cal y or cal yj These three commands make Unix generate a calendar of April 2012 a calendar of the current year and a calendar of Julian days of the current year respectively Tip The mouse isn t very useful at the command line You generally move the cursor only with the and keys The Delete key works as it always does You can use the mouse however to select text from anywhere in the window or other programs and paste it in at the prompt You can also use the mouse to drag an icon off your desktop into the Terminal wind
22. program that interprets the commands you ve typed passes them to the kernel the operating Bash evolved from the original sh shell which was named system s brain and then shows you the kernel s response the Bourne shell after its inventor Bash got its name then is In other words the shell is the Unix Finder It s the program ca Sa Is MAC OS X THE MISSING MANUAL that lets you navigate the contents of your hard drive see what s inside certain folders launch programs and docu ments and so on There are actually several different shells available in Unix each with slightly different command syntax All the popular ones like tcsh ksh andzsh come with Mac OS X You can choose among them as your default shell using of all things the Users amp Groups pane of System Preferences Click the enter your Administrator password and then Control click or You can open additional Terminal windows 100 or more depending on how many other programs are running by choosing Shell New Window sBasic Even slicker Ter minal lets you open multiple sessions in tabs just like with Safari by choosing Shell gt New Tab Basic Each window and tab runs independently of any others For proof try opening several windows and then running the cal command in each BONUS CHAPTER THE UNIX CRASH COURSE SS Unix Programs An enormous number of programs have been written for Unix And thanks to thou sands o
23. same name f Overwrites like named files without asking you first Actually this is how mv works if you don t specify otherwise n Doesn t overwrite like named files just skips them without prompting v Displays verbose fully explained explanations on the screen letting you know exactly what got moved Tip f you use a combination of options that appear to contradict one another like the f j and n op tions the last option farthest to the right wins By the way the mv command never replaces a directory with an identically named file It copies everything else you ve asked for but it skips files that would otherwise wipe out folders mkdir Create New Directories In the Finder you make a new folder by choosing File gt New Folder In Terminal you create one using the mkdir command for make directory Follow the command with the name you want to give the new directory like this mkdir Early iMovie Attempts the single quotes in this example let you avoid having to precede each space with a backslash The mkdir command creates the new directory in the current working directory although you can just as easily create it anywhere else Just add the pathname to your argument To make a new directory in your Documents gt Finished directory for example type mkdir Documents Finished Early iMovie Attempts The first quote comes after the so that it preserves that character s spe
24. the result of your calculation In computer land designates multiplication and represents division Note too that bc solves equations correctly it calculates multiplication and division before addition and subtraction and inner parentheses before the outer ones For more bc tricks and tips type man bc at the prompt kill Mac OS X offers no shortage of ways to cut the cord on a program that seems to be locked up or running amok You can force quit it use Activity Monitor or use kill The kill program in Terminal simply force quits a program as though by remote control It even works when you SSH into your Mac from a remote location as described in Chapter 21 All you have to do is follow the kill command with the ID number of the program you want to terminate And how do you know its ID number You start by running top described in a mo ment whose first column shows the PID process ID of every running program Tip Unless you also use sudo you can kill only programs you own those running under your account The operating system itself root is always running programs of its own and it s technically possible that other people dialing in from the road are running programs of their own even while you re using the Mac When you hear Unix fans talk about kill online they often indicate a number flag after the command like this kill 9 This flag is a noncatchable non ignorable kill MAC OS
25. very good start this prompt looks about as technical as computers get It breaks down like this office mac is the name of your Mac at least as Unix thinks of it It s usually the Mac s computer name as it appears in the Sharing pane of System Preferences indicates what folder you re in Figure 2 It denotes the working directory that is the currently open folder Remember there are no icons on the command line Essentially this notation tells you where you are as you navigate your machine The very first time you try out Terminal the working directory is set to the symbol but it s occasionally the name your Mac goes by on the Internet aor A Library bash 66 18 SS ibrar d fSystemsliararys Figure 2 On the Web Mac OS X s Terminal is one of the most often discussed elements of Mac OS X Dozens of step by step tutorials for perform taadi ing certain tasks circulate online saan usually without much annotation as to why you re typing what you re typing As you read this chapter remember that capital ization matters in Terminal even though it doesn t in the Finder As far as most Unix commands are concerned Hello and hello are two different things UP TO SPEED What s Been Lionized in Terminal Terminal received a makeover in Lion Mountain Lion For example its scroll bars are usually hidden and the W but ton sits in the corner of th
26. 8 45 Viscosity1 3 4 dmg com apple metadata kMDItemDownloadedDate 53 com apple metadata kMDItemWhereFroms 155 com apple quarantine 74 Aliases Aliases in Unix have nothing to do with traditional Macintosh icon aliases Instead Unix aliases are more like text macros in that they re longish commands you can trigger by typing a much shorter abbreviation For example remember the command for unlocking all the files in a folder It was sudo chflags R nouchg pathname To unlock everything in your account s Trash for example youd type sudo chflags R nouchg Trash Using the alias command however you can create a much shorter command unlock for example that has the same effect The alias command takes two arguments the alias name you want and the command it s supposed to type out like this alias unlock sudo chflags R nouchg Trash The downside is that aliases you create this way linger in Terminal s memory only while youre still in the original Terminal window As soon as you close it you lose your aliases When you get better at Unix therefore you can learn to create a bash_profile file that permanently stores all your command aliases Hint Open or create a file called bash_profile in your home directory and add to it one alias command per line nano One way to create and edit text files containing aliases and to perform other com mand related tasks is to use nano a popular text editor that
27. BONUS CHAPTER The Unix Crash Course operating system is only superficial The engine underneath the pretty skin is utterly different In fact it s Unix one of the oldest and most respected operat ing systems in use today The first time you see it you d swear that Unix has about as much in common with the original Mac OS as a Jeep does with a melon see Figure 1 A s you re certainly aware by now Mac OS X s resemblance to the original Mac What the illustration at the bottom of Figure 1 shows of course is a command line interface a place where you can type out instructions to the computer This is a world without icons menus or dialog boxes The mouse is almost useless here Surely you can appreciate the irony The brilliance of the original 1984 Macintosh was that it eliminated the command line interface that was still the ruling party on the computers of the day like Apple II and DOS machines Most nongeeks sighed with relief delighted that they d never have to memorize commands again Yet here s Mac OS X Apple s supposedly ultramodern operating system complete with a com mand line What s going on Actually the command line never went away At universities and corporations worldwide professional computer nerds kept right on pounding away at the little C or prompts appreciating the efficiency and power such direct computer control afforded them You re forgiven if your reaction to the idea of learning Unix i
28. O flag lists any file flags that have been set for each file In this case three of the files are listed with uchg which represents the user immutable locked flag The hyphen for the first listed file means no flags that is not locked Making Files Hide Back at the school computer lab youre still grumpy The students leave piles of file and folder icons splattered across all the Macs desktops and you ve had enough Not only is it a sign of laziness and disorganization but the icons cover the desktop picture of the hallowed school mascot the Southern hairy nosed wombat You ve warned them enough and now it s time for action No World of Warcraft at lunchtime unless the desktops are clean in 15 minutes As you finish writing the new rule on the whiteboard you turn to face the students Mac screens and youre stunned The full uncluttered image of your beloved mar supial gazes back from the Macs displays the offending icons are gone How could that be There hasn t even been time for the students to select all the icons and drag them to the Trash Apparently the students weren t as lazy as you thought They ve been learning the Way of the Terminal What they actually did was sweep all those icons under the rug Unix style with this command chflags hidden Desktop They manipulated another file flag called the hidden flag The command turns on the hidden flag for all files indicated by the asterisk
29. Package Contents A new Finder window opens revealing the contents of the iChat application package Open the Contents MacOS folder inside you ll find the individual iChat program file Nobody would ever bother opening iChat by double clicking this icon but it s possible You could inspect its permissions by highlighting the inner iChat icon choosing File Get Info and then expanding the Sharing and Permissions section The Unix way is faster In Terminal just use the Is command like this ls 1l Applications iChat app Contents MacOS The I flag produces a long list an expanded display showing extra information about each item in the directory in this case its single iChat file Terminal s response is something like this total 4544 rwxr xr x 1 root wheel 5989968 Jul 20 11 50 iChat Thanks to the option the first line displays the grand total size on disk of all the loose files in the directory 4544 It s measured in 512 byte blocks If you also included the k flag you would see this measurement in kilobytes Starting in Snow Leopard Apple began saving a lot of disk space by compressing many of Mac OS X s system files on the disk That s why the on disk size and actual size of a folder s contents don t always add up TextEdit for example seems to be 9 megabytes big in the Finder but Terminal reports its size at only 3 9 megs Next you see the name of the one inhabitant of the MacOS directory iC
30. Some interesting ones to try are xterm xcalc glxgears and xedit You can even add more X applications by downloading and compiling source code a daunting task for anyone new to Unix or through a ports system like MacPorts www macports org which provides software packages ported to Mac OS X for easier installation BONUS CHAPTER THE UNIX CRASH COURSE 49 Putting It Together For each file it gets sips first scales the image s largest dimension to 250 pixels and its other dimension proportionally That way any image will fit into a 250 x 250 pixel box on a Web page for example sips then sets the format s format of the image to JPEG and saves it with the correct jpg extension in the Stage directory The double ampersands amp amp at the end of this fragment tell the shell to run the next command only when it s successfully finished with the previous one If it fails the whole thing stops here So once sips is done with each file it gets from xargs the shell moves on to this echo put r Users chris Stage Incoming sftp chris coast photo com The sftp utility can run ftp instructions fed to it through a pipe in this case you need to put or upload the multiple r files that exist in Users chris Stage to the Incoming directory on the remote server The echo command pushes this instruction through the pipe to the sftp command which then connects to the Once you ve
31. TP site How would you go about it You could of course use Spotlight to search for all TIFF files that have Yosemite in their names But what if your images were named otherwise but kept in folders with Yosemite in their names You would have to find those folders first and then the TIFF files within them You could perform the next step scaling and converting the image either manually or by a preprogrammed script or Automator workflow using a program like Photoshop or even iPhoto Once the images were all done you d need to collect them and then use your favorite FTP program to upload them to the server If you ve mastered Unix though you could shave 12 minutes off of your workday just by changing to an empty working directory in this example Stage and typ ing this as one long line find type f ipath yosemite tif printO xargs 0 sips Z 250 s format jpeg out Stage amp amp echo put r Users chris Stage Incoming sftp chris coast photo com Even after almost 50 pages of Unix basics that mass of commands probably looks a tad intimidating And indeed if you ve never programmed before even the fol lowing breakdown may make your eyes glaze over Nevertheless pieces of it should now look familiar find type f ipath yosemite tif print0 This segment searches your home directory for files type f whose pathnames ipath meaning capitalization doesn t matter co
32. a directory If this x bit is turned on for a direc tory it s called the searchable bit as opposed to the execute access bit and it means you can make it the working directory using the cd command You still can t see what s in the folder if you don t also have read permissions but youre welcome to read or copy a file in it as long as you know its full pathname Group Detective Work Back to the task of keeping iChat from launching The x in every user category tells you that anyone can run this program Your mission should you choose to accept it is to change these settings so that one class of account holder can run iChat Admin but not another Standard As you ve seen every file s set of permissions identifies both an owner and a group The group that owns the iChat file is wheel but as you would expect the Admin class of users is part of the admin group though not part of wheel If you want to allow only administrators and anyone else in the admin group to run the program then you need to also change its group to admin You just have to make sure that no other account holders Standard ones are also part of the admin group That s easy enough to find out To find out what Unix groups you belong to type id in Terminal and press Return On the next line Terminal types out a list of items beginning with your account name that s your user ID your uid followed by the name of your primary group your gid N
33. and which cal for example Terminal responds with usr bin cal telling you that cal resides in the usr bin directory To get there use the open command in Terminal like this open usr bin A window opens in the Finder inside you ll find the cal icon Drag the icon to the right side of the Dock From now on when you click that Dock icon a new Terminal window opens auto matically displaying this month s calendar You ve shaved several precious seconds off the time it would have taken you to open iCal Services for Terminal Lion comes with a few useful new Services for the Terminal application see Chapter 8 for more on Services Note You won t see them however until you visit System Preferences gt Keyboard Keyboard Shortcuts click Services at left and inspect the Files and Folders list at right New Terminal at Folder New Terminal Tab at Folder When you ve selected a folder in the Finder you can choose these Services names from the Finder Services menu to open a new Terminal window or tab The selected folder becomes the current working directory Open man Page in Terminal Search man Pages in Terminal Start by selecting some text in a program that works with Services These Services open a new Terminal window displaying either the man page for the selected text if there is one or the result of a man k command on the selected text Changing Permissions Permissions is a largely invisible but
34. as you last left them But sometimes you might prefer your windows to be exactly as they were when you started your previous session and it would be a shame to lose all of that when you quit Terminal Fortunately you won t have to thanks to Window Groups Choose Window Save Windows as Group and name the group You ll be able to recreate your masterpiece when you return to Terminal by selecting that group name from Window Open Window Group Unlike resumed windows your original output won t be there but any commands you ve configured to run at startup will display their new output The Window Groups Preferences tab is just a place to view these groups and delete any you no longer need Using the pop up menu you can also export these groups as files to import into other machines or other accounts Connect to Server When you use Terminal to connect to other computers across a network a common Terminal task you use commands like ssh and ftp in conjunction with the other computers names or IP addresses For example you might type ssh bertha acmeco com or ssh 192 168 43 76 The trouble is these IP names and addresses are hard to rrmember and the numbers may change To make connecting easier Terminal can use the magic of Bonjour a networking feature in which Macs announce their presence to the network using their plain English names Bonjour lets you browse other Macs on your network just as you d browse them in the Find
35. cautious Ever since Tiger Mac OS X 10 4 the most common Unix file tools like cp mv tar and rsync with the E flag manage extended attributes correctly However as you explore with other tools it s wise to use them to duplicate rather than move files until you re sure all the bits stay together The command line tool for peeking in on your extended attri butes is xattr which you ll learn about later on in this chapter MAC OS X THE MISSING MANUAL BONUS CHAPTER THE UNIX CRASH COURSE 17 Working with Files and Directories 18 The syntax looks like this mv oldname newname For example to change your Movies directory s name to Films you d type mv Movies Films You can rename both files and directories this way Moving files and directories To rename a file and move it to a different directory simultaneously just replace the last portion of the command with a pathname To move the Tahoe movie file into your Documents directory and rename it LakeTahoe at the same time type this mv Tahoel mov Documents LakeTahoe mov All the usual shortcuts apply including the wildcard Here s how you d move everything containing the word Tahoe in your working directory files and directories into your Documents directory mv Tahoe Documents Option flags You can follow the mv command with any of these options i Makes Terminal ask your permission before replacing a file with one of the
36. cial meaning by not escap MAC OS X THE MISSING MANUAL ing it Thanks to Spotlight s constant eye on file activity the new directory appears immediately in the Finder Tip f there is no directory called Finished in your Documents directory you just get an error message un less you use the p option which creates as many new directories as necessary to match your command For example mkdir p Documents Finished Early iMovie Attempts would create both a Finished directory and an Early iMovie Attempts directory inside of it touch Create Empty Files To create a new empty file type touch filename For example to create the file practice txt in your working directory use touch practice txt And why would you bother For the moment you d use such new empty files primar ily as targets for practicing the next command rm Remove Files and Directories Unix provides an extremely efficient way to trash files and directories With a single command rm you can delete any file or directory or all those that youre allowed to access with your account type The dangers of this setup should be obvious especially in light of the fact that dele tions are immediate in Unix There is no Undo no Empty Trash command no Are you sure dialog box In Unix all sales are final The command rm stands for remove but it could also stand for respect me Pause for a moment whenever you re about to invoke i
37. ctures You ve just told Terminal to delete all data on all drives Because of the extra space the rm command sees its first rm command was the culprit Beware the Dread Typo Good thing you added the flag which instructs Mac OS X to ask you for confirmation before deleting each directory It s almost always a good idea to include i whenever you use sudo with rm History buffs and Unix fans may remember that Apple s first iTunes 2 installer released in October 2001 contained a tiny bug the tendency to erase people s hard drives Oops Apple hastily withdrew the installer and replaced it with a fixed one Behind the scenes an improperly formed 36 MAC OS X THE MISSING MANUAL To view the results of your handiwork right in Terminal issue this command Is 1O Pictures or any other path to a folder containing locked items That s the familiar Is list command that shows you what s in a certain directory followed by an flag for a more complete listing and an O flag that produces a flags column in the resulting table In any case Terminal might spit out something like this total 830064 rw r r 1 chris chris 158280000 Jun 16 20 05 Sunset jpg rw r r l chris chris uchg 58560000 Jun 16 20 05 Tahoe New Moon jpg rw r r l1 chris chris uchg 107520000 Jun 16 20 05 Tahoe jpg rw r r l chris chris uchg 100560000 Jun 16 20 05 Buddy Jpg The fourth column the product of the
38. d lose your work The options here let you configure when you want to be prompted if ever and even which processes you don t want Terminal to warn you about Keyboard These controls let you choose keyboard shortcuts that help you navigate your Terminal window or that send strings of canned text to the shell As your Unix prowess grows these shortcuts become more useful Tip For some Unix geeks the non Unixy location of the Control key has been frustrating enough to keep them from using Macs They use that key constantly and would rather not have to rewire their brains to handle the changed location But this problem is easily remedied In System Preferences in Keyboard amp Mouse the Modifier Keys button lets you swap the Control and Caps Lock keys functions allowing the confused pinkies of Unix heads to once again find their way BONUS CHAPTER THE UNIX CRASH COURSE 25 Terminal Preferences 26 Window Groups Once you ve gone to town with Terminal settings you might end up with a mosaic of windows spread across your display or displays your main Terminal window a couple of man user manual windows a top window showing all the running programs and so on You gotta love it Each window has its own color scheme and title to reflect what it s doing and all the windows are sized perfectly to contain their text output Thanks to Lion s Resume feature each time you open Terminal your windows re appear
39. ders are out of luck They ll have to actually pay attention in class chmod Change Mode The Unix command for changing file modes permissions is chmod for change mode Here s the command you use on the iChat file chmod o x Applications iChat app Contents MacOS iChat And here s how to understand it The command line begins naturally with the chmod command itself and ends with the pathname of the iChat file In between are three characters that make up the three parts of a mode change clause 0 x The first character o represents the class of user that the change affects In this spot you can type u to symbolize the file s owner g for its group o for other everyone else and a to indicate all three classes at once The second character represents the operation to perform which in most cases is either to add a permission use the symbol or remove one use the sign The final character specifies which permission to change r for read w for write or x for execute The complete chmod command provided above then says Remove the execute permissions for others which is precisely what you want to do Permission to Change Permissions If you actually try the chmod command described above however you get only an error message Operation not permitted Only the owner of an item can change its permissions And youre not iChat s owner root is that is Mac OS X itself BONUS CHAPTER
40. difications around In the mid 1970s the University of California at Berkeley became the site of especially intense Unix development Students and faculty there improved the Unix kerne the central essential part of the OS added features and wrote new Unix applications By 1977 they had enough additional software to release their own version of Unix the first of several Berkeley Software Distribution BSD versions As it happened the government s Defense Advanced Research Projects Agency DARPA was seeking a uniform portable OS to use for its growing wide area network origi nally called ARPAnet and now called the Internet DARPA liked Unix and agreed to sponsor further research at Berkeley In January 1983 DARPA changed ARPAnet s networking protocol to TCP IP and the Internet was born running mostly on Unix machines Cut to 1985 Steve Jobs left Apple to start NeXT Computer whose NeXTSTEP operating system was based on BSD Unix When Apple bought NeXT in 1996 Jobs NeXTSTEP eventually renamed OpenStep and its Terminal program came along with it The Unix that beats within Mac OS X s heart is just the latest resting place for the OS that Jobs s team developed at NeXT So the next time you hear Apple talk about its new op erating system remember that its underlying technology is actually over 40 years old BONUS CHAPTER THE UNIX CRASH COURSE For user friendliness fans Terminal doesn t get off to a
41. directories Trailers and Shorts Trailers is the current directory but you want to switch to the Shorts directory All you d have to do is type cd Shorts as illustrated in Figure 4 Keystroke Saving Features By now you might be thinking that clicking icons would still be faster than doing all this typing Here s where the typing shortcuts of the bash shell come in Tab completion You know how you can highlight a file in a Finder window by typing the first few characters of its name The tab completion feature works much the same way Over time it can save you miles of finger movement It kicks in whenever you re about to type a pathname Start by typing the first letter or two of the path you want and then press Tab Terminal instantly fleshes out the rest of the directory s name As shown in Figure 5 you can repeat this process to specify the next directory name chunk of the path Some tips for tab completion Capitalization counts Terminal adds backslashes automatically if your directory names include spaces signs or other special characters But you still have to insert your own backslashes when you type the hint characters that tip off tab completion If it can t find a match for what you typed Terminal beeps If it finds several files or directories that match what you typed Terminal beeps when you press Tab again terminal shows you a list of them To specify the one you really wanted type the nex
42. e For example to see a list of the files in the working directory that end with the letters te you could type Is te Terminal would show you files named Yosemite BudLite MAC OS X THE MISSING MANUAL Brigitte and so on and hide all other files in the list If the wildcard matches any directories you ll also see the contents of those directories as well just as though youd used ls with each of the full directory names Navigating in Unix Figure 5 AAN Arhi m 4 Top You type cd U and then press Tab AASL oe Dae ane Lart lagim Sun Sep 11 13 02 05 an eersdee Second from top Terminal finishes the direc 8 s8 acr christ cd yof tory name Users for you Third from top You type c and then press Tab Eae ft chris aS Bottom Terminal finishes the home un directory name chris You can also use tab completion to specify file names as when you type Is Movies R and then press Tab Terminal finishes the name Reviews doc Laat Login Sun Sep 11 23 82 BS an eps office seccs christ co flsersif Aare 48 chon bah SnI Loot logini Gun beep 11 iJ 020i on ttyst t oftice maer ghries ca eararce AD ft chris bash SAk aA Lait bagin un Sgp 11 130i on EEPABOB office esde chrii ed Ahiria cau chris tiigid chien ca Jere fener Leg Likewise to see which files and directories begin with Old you could type Is Old and press Return You d be shown only the names of icons in the work
43. e are ways to specify a directory that involve no typing at all One is dragging the icon of the directory you want to specify directly into the Terminal window Figure 3 should make this clear In Lion you can even drag the proxy icon in any Terminal window title bar Even slicker you can now drag a Finder folder icon onto Terminal s own application icon whether in the Dock or in a Finder window A new Terminal window opens for you pre parked in that directory MAC OS X THE MISSING MANUAL Dot Dot or Back Me Out So now you ve burrowed into your Movies directory How do you back out Sure you could type out the full pathname of the directory that encloses Movies if you had all afternoon But there s a shortcut You can type a double period in any pathname This shortcut represents the current directory s parent directory the directory that contains it To go from your home directory up to Users for example you could just type cd that is cd followed by a space and two periods You can also use the dot dot shortcut repeatedly to climb multiple directories at once like this cd which would mean switch the working directory to the directory two layers out If you were in your Movies directory would change the working directory to the Users directory Another trick You can mix the shortcut with actual directory names For example suppose your Movies directory contains two
44. e window so you can make its window go full screen Terminal windows new proxy icon in the title bar works like it has in other programs too You can 38 click it to see the parent folders of the current working directory click one and that folder opens in the Finder There are even new window themes in Preferences sSettings like Silver Aerogel It lets you see through your Terminal window to whatever is behind it the background appears blurry when your Aerogel window is active or crisp when it s inactive Terminal also benefits from Lion s Resume feature When you reopen Terminal all windows from your previous Terminal session reopen to their same working directories any text output from the previous session is preserved too Terminal s tabs and Dock icons have become animated They now indicate status changes of any inactive windows and Terminal s Dock icon displays a running count of any alerts bell signals received by inactive windows Finally windows you ve minimized to the Dock show Ter minal activity ive right on their icons Try it Execute a long running command like s R which lists the contents of your entire drive and then minimize that window Now look at the Dock icon and watch the tiny lines fly by That tilde symbol is important shorthand it means your own Home folder It s what you see the first time you start up Terminal but you ll soon be seeing the names of other fold
45. econdary permission system to help make some of its new features work These access control lists ACLs provide much finer control of permissions allowing you for example to assign multiple owners and groups to a single file ACLs are also behind the file sharing permissions described on page 534 Not all files or even most files on your Mac use ACLs But when they re present the ACL permissions over ride the file s Unix permissions For details on ACLs download this chapter s free appendix Access Control Lists from the Missing CD page at wwwmissingmanuals com Looking at Permissions In general when you double click a file icon in the Finder it opens either as a program or opens into a program if it s a document BONUS CHAPTER THE UNIX CRASH COURSE Changing Permissions 29 Changing Permissions 30 But most Mac OS X application icons in the Finder are really folders posing as single files Inside the folder or package are all the files that application depends on to run including the actual application file itself the one that opens when you double click the package icon If you turn off the execute permission for that inner nugget you prevent it from running and as in this classroom example you can turn it off for certain kinds of account holders and not others To inspect the permissions for iChat open the Applications folder Control click the iChat icon From the shortcut menu choose Show
46. ed with caution At the outset at least you should use it only when you ve been given specific steps to follow as in this chapter Now sudo asks for your usual login password just to confirm that you re not some seventh grader up to no good If you are indeed an administrator and your password checks out sudo gives you a 5 minute window in which by prefacing each command with sudo you can move around as though you re the all high master root account holder If you don t use sudo again within a 5 minute span you have to input your password again The last step then is to change the iChat s group to admin chgrp Change Group The Unix command for changing a file s group ownership is chgrp for change group and it will do the deed sudo chgrp admin Applications iChat app Contents MacOS iChat By this point you should be able to guess that this command allows you with sudo to change the group ownership to admin of the file Applications iChat app Contents MacOS iChat Now whenever anyone who isn t an administrator tries to open iChat its icon bounces in the Dock until you click it allowing iChat to die painlessly To restore its original permissions use the same commands but in the chmod com mand replace the with a like this sudo chmod o x Applications iChat app Contents MacOS iChat Then rerun the chgrp command but replace admin with wheel sudo chgrp wheel Applications iChat app Contents MacOS
47. er Chapter 13 To get started choose Shell New Remote Connection Continue as shown in Figure 9 Tip Even if the remote machine isn t running Bonjour you can still add its address to the Server list manually by clicking the button below it Likewise all command lines entered in the bottom field get added to the pop up menu beside it allowing you to quickly reconnect without having to browse at all Terminal Tips and Tricks After you ve used Terminal awhile you may feel ready for a few of these power tips MAC OS X THE MISSING MANUAL Split Windows If you choose Window gt Split Pane 36 D you wind up splitting your Terminal win dow into an upper pane and a lower pane That can be handy when you keep certain scripts running all the time The two panes mirror the same command but now you can scroll to different positions within each pane keeping watch over different parts of the same output simultaneously Terminal Tips and Tricks Figure 9 Ar From the left side choose the service you s want from the right choose from a list of machines whose Remote Login checkboxes service saver are turned on in the Sharing panel of Sys Terure Shell ahi tem Preferences Type your account name Secure File Transfer alte into the User box As you adjust the connec ee a tion options the box at the bottom shows oo the Unix command you re building Click Connect to open a new Terminal window and send that command
48. ers here office mac Users or office mac System Library for example More on this slash notation on page 26 Note Before Apple came up with the user friendly term folder to represent an electronic holding tank for files folders were called directories In this chapter you ll encounter the term directory almost exclusively In any discussion of Unix directory is simply the correct term Besides using a term like working folder within earshot of Unix geeks is likely to get you lynched e chris begins with your short user name It reflects whoever s logged into the shell see the box on the facing page which is usually whoever s logged into the Mac at the moment As for the sign think of it as a colon In fact think of the whole prompt shown in Figure 2 as Unix s way of saying OK Chris Pm listening What s your pleasure Unless you ve fiddled with Terminal s preferences the insertion point looks like a tall rectangle at the end of the command line It trots along to the right as you type Bash Terminal and Shells One Unix program runs automatically when you opena right click your account name in the list choose Advanced Terminal window bash It s Apple s chosen shell for Mac Options There on the Advanced Options panel you ll find OS X 10 7 the Login Shell box where you can make the change But on a Clean installation of Lion Terminal comes set to use bash A shell is a Unix
49. es command file you would type chmod u x Processimages command With just a few more keystrokes you could modify that command to collect some files lock them and place copies of each in every account holder s home directory as well as several different servers at the same time What s more it emails you a report when it s done Using launchd you could even configure this routine to trigger itself automatically every day at 11 00 p m Considering the hundreds of Unix programs included with Mac OS X and the thousands of others available on the Internet the possibilities are limitless MAC OS X THE MISSING MANUAL
50. ext are the names of all the groups that include your account The Mac refers to accounts and groups by number which are listed here If you have an Administrator account it s probably something like uid 506 chris gid 20 staff groups 20 staff 217 com apple access_loginwindow 402 com apple sharepoint group 1 403 com apple sharepoint group 2 401 com apple access_screensharing 12 everyone 33 _ MAC OS X THE MISSING MANUAL appstore 61 localaccounts 79 _appserverusr 80 admin 81 _appserveradm 98 _ Ipadmin 100 _lpoperator 204 _developer But you want to find what groups incorporate Standard account holders To determine what groups someone else s account belongs to type id casey or whatever the account name is You ll probably see that Casey doesn t belong to the admin group And in fact that s true for all Standard account holders If you prefer a little less output the groups command used similarly will show you only the group names All right then The admin group contains only Admin users As far as permissions are concerned then Standard account holders fall into the everyone else category You just need to turn off iChat s execute permissions for everyone else and change iChat s group to admin to complete your task Doing so allows only the file s owner root and members of its group admin to execute the file that is to open the program All other account holders meaning Standard account hol
51. f open source developers programmers all over the world who collaborate and make their work available for the next round of modification much of this software is freely available to all including Mac OS X users Each Unix command generally calls up a single application or process as geeks call it that launches performs a task and closes Many of the best known such applica tions come with Mac OS X Here s a fun one Just type uptime and press Enter or Return That s how you run a Unix program Type its name and press Return On the next line Terminal shows you how long your Mac has been turned on continuously It shows you something like 13 09 up 8 days 15 04 1 user load averages 1 24 1 37 1 45 meaning your Mac has been running for 8 days 15 hours nonstop You re finished running the uptime program The prompt returns suggesting that Terminal is ready for whatever you throw at it next Try this one Type cal at the prompt and then press Return Unix promptly spits out a calendar for the current month OfficeMac chris cal August 2011 Su Mo Tu We Th Fr Sa L 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 OfficeMac chris UP TO SPEED Pathnames 101 In many ways browsing the contents of your hard drive us evel to the next nested folder then to the next one and ing Terminal is just like doing so with the Finder You start with a folder and move down
52. g buttons and dragging icons And it gives you a fascinating glimpse into the minds and moods of people who live and breathe computers If you ve ever dabbled in Excel macros experimented with AppleScript or set up a Mac on a network you already know the technical level of the material you re about to read The Unix command line may be unfamiliar but it doesn t have to be especially technical particularly if you have some recipes to follow like the ones in this chapter Note Unix is an entire operating system unto itself This chapter is designed to help you find your footing and decide whether or not you like the feel of Unix If you get bit by the bug Google can help you find endless reams of additional Unix help MAC OS X THE MISSING MANUAL Terminal The keyhole into Mac OS X s Unix innards is a program called Terminal which sits in your Applications Utilities folder see Figure 2 Terminal is named after the terminals computers that consist of only a monitor and keyboard that used to tap into the mainframe computers at universities and corporations In the same way Terminal is just a window that passes along messages to and from the Mac s brain The first time you open Terminal you ll notice that there s not much in its window except the date time and source of your last login and the command line prompt Figure 2 UP TO SPEED Mac OS X s Unix Roots In 1969 Bell Labs programmer Ken Thompson
53. g window with Tem P a _ one quick click AE Homebrew Tt in the Terminal at hale de Use bald isats T icid Text Inspector choose SES wan px i Alle blinking tea z Terminal gt Show i E Display ANS colors ad Foret Inspector or Use bright colers for bold texi press 3 1 mee Navel ANSI Colori EiT Ocean E i mm iz Miral al 1 I Gright Camber E gies rm aa Red Sands ae sce Uriari vertes Gar EA ihe Aenage a Bink curias Background Color Not only can you set the background color but you also can set its opacity as well making your Terminal windows translucent a sure way to make novices fall to their knees in awe Just drag the slider to the right and watch the background of the active window nearly disappear like the Cheshire Cat leav ing only text If you like the translucency but find the background too distracting use the blur slider to fuzz it out You can even set opacity and blur separately for active and inactive windows MAC OS X THE MISSING MANUAL Tip This effect looks especially cool if you make the Terminal window black with white or yellow writing Preferences Background Image If you prefer to look at your favorite moonscape or WWE wrestler as you work at the command line you can choose an appropriate image file here Or choose an entire folder of images Terminal will choose one randomly for the background of each newly opened window Scrollback A
54. gained some experience with Unix commands and programs like these Putting It Together youll find it fairly easy to adapt them to your own tasks For example here s a more eee versatile command that searches a directory called Projects for all TIFF files modified after 6 00 that morning converts them to thumbnail sized JPEGs plops them into the images directory of your FTP accessible Web server and then moves them all to your Backup directory cd Stage amp amp find Projects type f iname tif newermt 6 00 printO xargs 0 sips Z 128 s format jpeg out Stage amp amp ftp u ftp carlos birdie ftp coast photo com htdocs images amp amp mv Backup POWER USERS CLINIC The Root Account specified remote account chris coast photo com and once you ve provided your password performs the upload When you press Return or Enter after this gigantic command Mac OS X scans all the directories inside your home directory rounds up all the Yosemite related images scales them converts and renames them and then uploads each to the remote directory POWER USERS CLINIC The Famous Animated Desktop Trick It was one of the first great Mac OS X hacks to be passed around the Internet the classic screen saver on the desk top trick In this scheme your desktop shows more than some wussy motionless desktop picture It actually displays one of the Screen Effects animation modules Start by choosi
55. hat If there were more you would see each item on its own line But what is rwxr xr x Is Ter minal having a meltdown Not at all youre just seeing more Unix shorthand listed in what are supposed to be helpful columns Figure 10 breaks down the meaning of each clump of text Type The first character of the line indicates the file type usually d a directory 1 a symbolic link the Unix version of an alias or as in this case a hyphen a file File mode Rammed together with the type like this rwxr xr x is a string of nine characters It indicates in a coded format the actual access permissions for that item as described in the next section Owner Terminal s response also identifies the account name of whoever owns this file or directory which is usually whoever created it Remember root means that MAC OS X THE MISSING MANUAL Mac OS X itself owns it That s why even administrators generally aren t allowed to delete directories that bear root ownership Note In the Finder s Get Info windows you may see ownership listed as System That s Apple s kinder gentler term for root Changing Permissions of information that tell you who s allowed to do what sad arr Owner Group Other sntjusta string oi rangom Ajg ermission ermission ermission letters it s three distinct sets yp P aons P SSIONS P SSIONS mm i rwWwWxr xr x Group After the owner comes the na
56. he command that refine how the command should run Remember the calendar example When you wanted the April 2011 calendar you typed cal 4 2011 The 4 and 2011 parts were the arguments that is everything you typed after the command itself To see a list of the files in your Documents directory then you could just type Is Users chris Documents Better yet because the symbol is short for my home directory you could save time by typing s Documents The pathname Docu ments is an argument that you ve fed the Is command About flags As part of acommand s arguments you can sometimes insert option flags also called switches modifying characters or short phrases that affect how the command works just like option settings do in GUI applications In the calendar example you can type cal y to see a full year calendar the y part is an option flag Option flags are almost always preceded by a hyphen although you can usually run several flags together following just one hyphen If you type Is al both the a and l flags are in effect Here are some useful options for the ls command MAC OS X THE MISSING MANUAL a The unadorned ls command even displays the names of invisible files and fold ers at least by the Finder s definition The Unix shell uses its own system of denot ing invisible files and folders and ignores the Finder s That doesn t mean you re seeing everything files
57. he file or folder you specified is now compressed with the suffix gz combined with the suffix tar or both with the suffix tar gz or zip Unfortunately neither the command line zip nor the gzip utility handle extended attributes properly see the next page so stick to tar with gzip if you want to create guaranteed Mac friendly archives The best format then is a gzipped tarball which the Finder will properly open with a double click You can also use these utilities to open combined and compressed files but they can easily overwrite existing items of the same name if youre not careful Use the Finder or StuffIt Expander to eliminate that worry Note The gzip command deletes the original file after gzipping it The tar and zip commands on the other hand stuff things but leave the originals alone top table of processes When you type top and press Return you get a handy table that lists every program currently running on your Mac including the obscure background ones you probably never even knew existed Figure 11 You also get statistics that tell you how much memory and speed CPU power they re sucking down There s also a line that shows the amount of data moved to and from the network as well as the amount read or written to disk since you last started your Mac In this regard top is similar to Activity Monitor Tip f you type top u you get a list sorted by CPU usage meaning the power hungr
58. he user immutable flag Not even the superuser is allowed to change move or delete a file whose user immutable flag is turned on The command you need to change such flags is chflags short for change flags of course You can follow the chflags command with three arguments its own option flags the file flags and the pathname of the file whose flags are being changed In this case the flag you care about is called uchg short for user changeable in other words this is the immutable flag To protect all the Tahoe shots in one fell swoop then here s what youd type at the prompt chflags uchg Pictures Tahoe The asterisks are wildcards that mean all files containing the word Tahoe in their names So in English you ve just said Change the immutable flag the Locked checkbox setting for all the Tahoe files in my Pictures folder to locked Tip To unlock a file thus turning off its uchg flag just add the prefix no like this chflags nouchg Pictures Tahoe UP TO SPEED disastrous like this Use sudo with caution especially with the rm command pathname argument as being only the root directory The Even a single typing error in a sudo rm command can be r flag means and all directories inside it Suppose for example that you intended to type this sudo rm ri Users Jim Pictures but you accidentally inserted a space after the first slash sudo rm ri Users Jim Pi
59. iChat Note Apple has these default permissions set for a reason utmost security While your changes won t im mediately let the bad guys in it s best not to leave these permissions in place unless you really need them In any case whenever you run the Mac s Repair Permissions function either automatically which happens each time you install a Mac OS X update or manually using Disk Utility iChat returns to its original permis sions settings You have to rerun the command if you want its protections in place Protecting Files En Masse It could happen to you You ve got yourself a folder filled with hundreds of files downloaded photos from your digital camera for example Most are pretty crummy BONUS CHAPTER THE UNIX CRASH COURSE Changing Permissions 35 Changing Permissions but the ones you took in Tahoe which therefore have Tahoe in their file names are spectacular You want to protect those files from deletion without having to turn on the Locked checkbox page 95 of every file individually Here again you could operate in the Finder just like ordinary mortals You could use Spotlight to round up all files with Tahoe in their names highlight them in the search results window choose File gt Get Info and then turn on Locked for all of them at once But doing it the Unix way builds character When you turn on a file s Locked checkbox Mac OS X turns on an invisible switch known to Unix veterans as t
60. in the Desktop folder and so their icons disappear The actual file is still there but you just can t see it in the Finder anymore Of course youre not about to let some punk kids pull one over on you In your copy of Terminal you deftly type chflags nohidden Desktop to bring the icons back BONUS CHAPTER THE UNIX CRASH COURSE Changing Permissions 37 Changing Permissions 38 The students have 13 minutes left to really clean their desktops 20 Useful Unix Utilities So far you ve read about only a handful of the hundreds of Unix programs that are built into Mac OS X and ready to run Yes ls and sudo are very useful tools but they re only the beginning As you peruse beginner level Unix books and Web sites for ex ample you ll gradually become familiar with a few more important terms and tools Here s a rundown of some more cool and very safe programs that await your ex perimentation Tip f you don t return to the prompt after using one of these commands type q or in some cases quit and then hit Return bc Mac OS X and Windows aren t the only operating systems that come with a basic calculator accessory Unix is well equipped in this regard too When you type bc and hit Enter you get a copyright notice and then nothing Just type the equation you want to solve such as 2 2 or 95 97 456 2 65 or 2 3 165 95 2 5 2 5 and then press Return On the next line bc instantly displays
61. ing directory called Old Yeller Old Tahoe Footage Olduvai Software and so on If you add the asterisk before and after the search phrase you find items with that phrase anywhere in their names Typing Is jo will show you the files named Mojo johnson Major Disaster and so on Tip Using by itself means show me everything To see a list of what s in a directory and in the directories inside it as though you d highlighted all the folders in a Finder list view and then pressed 38 right arrow just type s Directory Switching A hyphen after the cd command means Take me back to the previous working directory For example if you changed your working directory from Movies Movie 1 to Documents Letters simply enter cd to change back to Movies Movie 1 Use cd a second time to return to Documents Letters Note the space between cd and the hyphen BONUS CHAPTER THE UNIX CRASH COURSE 13 Navigating in Unix Tip f you re doing a lot of switching between directories you ll probably find it quicker to open and switch between two Terminal windows or tabs each with a different working directory The Shortcut You already know that the tilde character is a shortcut to your home directory But you can also use it as a shortcut to somebody else s home directory simply by tacking on that person s account name For example to change to Miho s home di 14 rectory use cd miho
62. inside it hie Remie Connection User chris SSH LAubomatec jah p 22 chriv Mibod Mackack Pro loca Switching Windows You can switch among your various Terminal windows by pressing 88 1 8 2 and so on up to 88 9 You ll be able to identify the windows easily if you choose to include the Command key in the title bars Use the Window section of the Settings Preference pane Noncontiguous Selection You can select blobs of text just as in Microsoft Word or TextEdit To select a single rectangle of text anywhere in the window Option drag through it To select multiple rectangles Option 86 drag You can then copy and paste just those selected blobs Double Clickable Unix Tools Most people are used to thinking of Unix applications as programs you run from within Terminal Many though appear in the Finder as regular old icons and you can open them by double clicking just as you would a traditional Mac OS X program BONUS CHAPTER THE UNIX CRASH COURSE 27 Terminal Tips and Tricks 28 This trick isn t very useful for commands that require flags But for some like cal click ing provides a quick way to run the program especially if you keep it in your Dock To double click a Unix program though you first have to find it and that may not be easy Mac OS X s Unix directory structure is labyrinthine indeed But why not ask Terminal where the program is You can do exactly that using the which comm
63. le configuration allowing you to recreate those layouts in an instant Configure your settings using Terminal s Preferences panel Figure 8 which you get to by choosing Terminal Preferences of all places Startup The Startup tab lets you configure what Settings or Window group Terminal should use to open in case you want something besides the factory settings This tab also gives you another way to switch from bash to a different default shell Where it says Shells open with choose command complete path and then type bin bash for bash or bin tcsh for tcsh New Terminal windows will then open with that shell Using two other pairs of pop up menus one for new windows and the other for new tabs you can answer two questions First Do you want new windows or tabs to open with the same settings as the current active one or to use the default settings Second Do you want new windows or tabs to open in the same working directory as the current active one or to use the default working directory Settings This tab is the heart of Terminal s preferences management On the left a list of set tings categories On the right the options for the currently selected category Terminal comes with several preconfigured settings and you can add and remove these and your own using the and buttons below the list To restore all the options for the prepackaged settings to their original state select Restore Defaults fro
64. m the menu To see your changes reflected instantly in a Terminal window make sure the window youre watching is using the same setting youre modifying Text Here s where you control what the insertion point looks like along with choices of fonts and colors Note No matter what font you choose typed characters align vertically Terminal spaces them out that way even if they re not monospaced fonts like Courier Monaco or Menlo Terminal s standard font BONUS CHAPTER THE UNIX CRASH COURSE Terminal Preferences 23 Terminal Window Preferences Title Turn on the elements youd like the current Terminal window to display in 24 the title bar Remember your preferences can be different for each setting group you might therefore want the windows title bars to identify the differences e Window Size The Dimensions boxes affect the width in characters columns and height in lines rows of new Terminal windows Of course you can always resize an existing window by dragging its lower right corner As you drag the title bar displays the window s current dimensions a Settings Figure ae Here in Settings 4 z Til you can tailor the J A is la ae Lad look and person ee ee eee ality of Terminal to within an inch ET l Tear Window Shell o Keyboard Advanoed of its life Later Delan 2 _ Fami you can apply a saved set of set Menig Reguiar 11 pg Change ETT Grass tings to an exist in
65. mand including all possible options and arguments in a concise formula For example the synopsis for du disk usage is as follows du H L P a s d depth c h k m g x I mask file That line shows all the flags available for the du command and how to use them Brackets surround the optional arguments All the arguments for du are optional BONUS CHAPTER THE UNIX CRASH COURSE Working with Files and Directories 21 22 nL La Lis REIS La AE CP CALS TUebdetgkhiklescgaritencl file aal ESEGCECPRT Ig 3 4 r work Lava Vertical bars called pipes indicate that you can use only one item of the group separated by pipes at a time For example when choosing options to use with du you can use either H L or P not two or all three at once The word file in the synopsis means type a pathname here The ellipsis fol lowing it indicates that you re allowed to type more than one pathname Description Explains in more detail what the command does and how it works Often the description includes the complete list of that command s option flags For more information on using man view its own manpage by entering what else man man Tip The free program Bwana available for download at www missingmanuals com is a Cocoa manual pages reader that provides a nice looking easier to control window for reading manpages Fig
66. me of the group that owns this file or directory Wheel as in big wheel indicates the group with the highest powers adminis trators are not part of this group the admin group contains all administrators Pathname At the end of the line following the file s size and date comes the path of this file or directory relative to the listed directory File Mode Code To understand the coded nine character file mode section you need a good grasp of the topics covered in Chapter 12 There you ll find out that as you create new files and directories you can specify who else is allowed to see or make changes to them In fact you can specify these permissions for three different categories of people the owner usually yourself your group and everyone else The file mode column is made of three subcolumns Figure 10 which correspond to those same three categories of people owner group and everybody else Within each sequence three characters describe the read r write w and execute x permissions that this person or group has to this file or directory more on these concepts in a moment A hyphen means Nope this person isn t allowed this kind of access In Figure 10 you can see that if you were the owner of this file you could do anything you want to it because there are no hyphens There s an x in the other columns too meaning that anyone can execute launch this file Since there s
67. members routinely use iChat to communicate Talking out loud after all is so 20th century Use Parental Controls You can open System Preferences click Accounts and click Parental Controls You d then click to configure Finder amp System select Some Limits and turn off the iChat checkbox from the list of allowable applications Repeat 124 times Though it is nice that Screen Sharing lets you do this remotely Buy install and configure Mac OS X Server Then you can create and configure workgroups with any permission settings you want Apple offers a four day train ing course if you get stuck Use Terminal Go to a Mac fire up Terminal and type a quick command to turn off iChat s execute permissions for Standard account holders This process wont affect the Computer Club because its members all have Administrator accounts Repeat only 24 times In fact if walking to each machine is too much work you can even use the ssh technique described in Chapter 21 to run the command remotely from a single machine while seated in the comfort of your own teacher s chair This of course is by far the best solution It ll take several pages to work through this example But in the process you ll learn an amazing amount about Terminal and the Unix underpinnings of Mac OS X Note The original Unix permission system has been around longer than disco and still serves well in Mac OS X But Leopard Mac OS X 10 5 introduced a s
68. mpts to remove the files without asking you for confirmation regardless of the file s permissions The command proceeds full speed ahead e i for interactive makes the Mac ask for confirmation before each deletion P securely overwrites the file three times It s an alternative to the srm command described next srm Secure Removal srm is a command line version of the Finder s Secure Empty Trash function page 95 It lets you choose just how thoroughly Mac OS X scrubs the hard drive spot where the deleted file once sat The srm utility lets you specify three general levels of deletion Simple The s flag tells srm to perform a simple secure removal overwriting the deleted material with random data just once It s faster than the Finder s Secure Empty Trash but not as thorough Medium The m flag designates medium level which overwrites the unwanted data seven times with various types of random and not so random data This is similar to what you get when you use the Finder s Secure Empty Trash command and it s thorough enough to meet U S Department of Defense security requirements Strong If you don t specify either s or m srm will perform a strong secure removal That entails recording over the spot where the deleted file sat 35 times each time using a different string of data as specified by the Gutmann algorithm And what is the Gutmann algorithm A series of data patterns that make recov er
69. ms columns 9 through 14 provide details about the memory usage of each listed program The one you care about is the RPRVT Resident Private column which shows how much memory each program is actually using at the moment This number goes up and down as you work illustrating a handy trait of Mac OS X Programs don t just grab a chunk of memory and sit there with it They put that RAM back in the pot when they don t need it BONUS CHAPTER THE UNIX CRASH COURSE 47 20 Useful Unix Utilities 48 files The problem with both of these programs is their utter lack of security they transmit passwords and data across the network unencrypted The modern secure versions of these programs are SFTP which you use much like FTP and the previ ously introduced SSH Tip Unlike FTP which requires a remote FTP server SFTP needs the SSH or Remote Login service run ning on the remote host Putting It Together The Unix syntax and vocabulary presented in this chapter is all well and good and it ll give you the rosy glow of having mastered something new But it still doesn t entirely explain why Unix gives programmers sweaty palms and dilated pupils The real power of Unix comes down the road when you start stringing these com mands together Suppose for example you want to round up all the TIFF image files related to your Yosemite project scale them to a common size convert them to JPEG files and copy them to an F
70. ng the screen saver module you prefer using the Screen Effects panel of System Preferences The one called flurry makes a good choice Then in Terminal type System Library Frameworks Screen Saver framework Resources ScreenSaverEngine app Contents MacOS ScreenSaverEngine background amp Finally press Return Note that there are no Returns in the command even though it appears broken onto more than one line here Presto The active screen saver becomes your desktop picture Fall back into your chair in astonishment Once you ve regained your composure look in the Terminal window again The number that follows the 1 in the fol lowing line is the process ID of your background desktop program You ll need that number when it comes time to turn off the effect which is a good idea since the desktop screen saver business drains a massive amount of your Mac s processing power The whole thing is a gimmicky showoff stunt you ll generally want to turn off before conducting any meaningful work To turn off this effect type kill 496 or whatever the process ID is and then press Return And if you get tired of typing out that long command download xBack from www gideonsoftworks com xback html It s a simple piece of shareware that lets you turn this effect plus many additional options on and off with the click of a mouse Standard Administrator Managed Sharing Only and Guest aren t the only kinds of accoun
71. ntain the word Yosemite and end in tif Remember the asterisks here are wildcard characters The command so far makes a list of all matching files which it keeps in its little head MAC OS X THE MISSING MANUAL The printO command formats this list of found files pathnames separating them with the null character a special character programmers use to indicate where one string of text ends and another begins instead of the usual spaces It lets the command work with pathnames that contain spaces a common occurrence on Macs but a rarity in Unix You ll see how it does this shortly Then comes the pipe the vertical bar which you can use to direct the results output of one command into the input of another In this case it sends the list of found pathnames on to the next command xargs 0 sips Z 250 s format jpeg out Stage amp amp xargs is an argument builder In this case it builds an argument from the list of files it received from the find command and provides it to sips for processing In other words xargs hands a list Putting It Together of files to sips and sips runs the same command on each one The 0 flag tells xargs that the pathnames are separated by the null character Otherwise xargs would separate pathnames at each space character which would choke sips UP TO SPEED X11 If you ve ever poked around in your Applications Utilities folder you might have spotted the program called X11
72. of their EAs gets its own line What you ll find in common to all of these files is that they hold a com apple quarantine EA You know how the first time you open a program on your Mac you get a warning dialog box asking if youre sure Now you know how the Mac knows that this is the first time you ran it That detail was stored as one of its extended attributes If you really can t stand those messages you could use another Unix command to prevent the nag box from appearing For example before installing Viscosity you could simply remove the quarantine EA from its downloaded disk image file using the xattr command s d flag like this xattr d com apple quarantine Viscosity1 3 4 dmg You can also use the s command to see EAs When you use just the l flag with ls files with EAs show an sign at the end of the permission codes Process ID ee a a a T Virtual memory use Figure 11 The top display remains onscreen z automatically updating itself as tirz you work until you type q to quit the program The plain English program names are in there 13 somewhere FT TTTTE Ea TTT Program name Memory use MacChris Downloads ls 1 Viscosityl 3 4 dmg rw r r 1 chris staff 6653836 Aug 2 08 45 Viscosity1l 3 4 dmg To see what those EAs are add the flag MAC OS X THE MISSING MANUAL MacChris Downloads chris ls 1 Viscosity1 3 4 dmg rw r r 1 chris staff 6653836 Aug 2 0
73. ow as shown in Figure 3 Figure 3 aren This may be the quickest way of all itil oin to identify a directory or file you want to manipulate Don t type anything When you drag icons directly from the desktop into a D chrii a Terminal window the icon s path officesmati ches name appears automatically at the insertion point Terminal even adds backslashes to any special charac ters in these pathnames for you a necessary step known as escaping the special characters SHTA CENA CECE O ill Bae Tra hers Pires Meret l Navigating in Unix If you can t see any icons for your files and folders how are you supposed to work with them You have no choice but to ask Unix to tell you what folder youre looking at using the pwd command what s in it using the ls command and what folder you want to switch to using the cd command as described in the following pages pwd Print Working Directory or Where am I Here s one of the most basic navigation commands pwd which stands for print working directory The pwd command doesn t actually print anything on your printer Instead the pwd command types out on the screen the path Unix thinks youre in the working directory Try typing pwd and pressing Return On the next line Terminal may show you something like this Users chris Movies BONUS CHAPTER THE UNIX CRASH COURSE Navigating in Unix Terminal is re
74. property list files in System Library LaunchDaemons but be careful not to mess with anything else in there Note Some other Unix systems and versions of Mac OS X use the cron utility to run these jobs cron also exists on Lion and will start working as it does elsewhere the minute you add a new cron job See the cron and crontab manpages for details MAC OS X THE MISSING MANUAL SIps Sips Scriptable Image Processing System an Apple Unix utility included with Lion lets you process graphics files like TIFF JPEG and GIF files from within Terminal You can use sips to get more information about such files type size or attached ColorSync profile for example or to remove or attach ColorSync profiles Better still sips can modify the images by scaling rotating flipping or converting them to other formats like PNG or Photoshop You can also generate custom Finder icons for images files without them Consult the sips manpage to see the list of image file properties that sips can work with For example to flip a digital photo called TenLakes jpg vertically and save the flipped version with the name TenLakesFlipped jpg type this sips f vertical TenLakes jpg out TenLakesFlipped jpg If you fail to include the out option and a new filename sips will permanently transform the original image file instead of spinning out a new one You can even include multiple sips actions in one command So for example
75. rking directory like this cp Documents Reviews doc Notice the space and the period after Reviews doc Multiple files You can even copy several files or directories at once Where you d normally specify the source file just list their pathnames separated by spaces as shown in Figure 6 You can also use the wildcard to copy several files at once For example suppose you ve got these files in your iMovie Projects directory Tahoel mov Tahoe2 mov Tahoe3 mov Tahoe4 moy Script doc and Tahoe Project File Now suppose you want to copy only the QuickTime movies into a directory called FinishedMovies All youd have to do is type cp mov FinishedMovies and press Return Mac OS X instantly performs the copy If you wanted to copy all those files not just the movies to another directory youd use the by itself like this cp Finished Movies Unfortunately if the iMovie Projects directory contains other directories and not just files that command produces an error message The Unix cp command doesn t copy FREQUENTLY ASKED QUESTION The Slash and the Colon directories within directories unless you explicitly tell it to using the R option flag Here s the finished command that copies everything in the current directory both files and directories into FinishedMovies cp R FinishedMovies Working with Files and Directories Figure 6 The first argument of this command lists two different l J co
76. s For goodness sake can t I finish learning one way to control my new operating system before I have to learn yet another one Absolutely You never have to use Mac OS X s command line In fact Apple has swept it far under the rug obviously expecting that most people will use the beautiful icons BONUS CHAPTER THE UNIX CRASH COURSE 1 The Unix Crash Course and menus of the regular desktop There are however some tasks you can perform only at the command line although fewer with each release of Mac OS X For intermediate or advanced Mac fans with a little time and curiosity however the Diitijp seu cen boi Dien leach Public Figure 1 Top What most people think of vs when they think Macintosh is a graphical user interface GUI one that you control with aj al a mouse using icons and menus to represent files ann ft chris bash 58st E and commands Muri Piiiaes ottici chess Le Bottom Terminal Desktop Downleads Mewies letures offers a second way to control Mac OS X a com mand line inter face which you operate by typing out programming commands Document g Lor Ery Aus BPE Ler mat is Caras i command line opens up a world of possibilities It lets you access corners of Mac OS X that you can t get to from the regular desktop It lets you perform certain tasks with much greater speed and efficiency than youd get by clickin
77. s an improved version of the pico editor see Figure 12 In fact if you try to run pico nano opens instead As you ll discover just by typing nano and pressing Return nano is a full screen Unix application You enter text in nano much as you do in TextEdit yet nano is filled with features that are specially tailored to working with Unix tasks and commands Nor is nano the only text editor that s built into the Unix under Mac OS X Some Unix fans prefer the more powerful and complex vim or emacs in the same way that some people prefer Microsoft Word to TextEdit date Used all by itself the date command simply displays the current date and time How ever you can use its long list of date conversion specifications enter man date to see all of them to format the date string in any conceivable way Begin the string with a and then enter the formatting you like mixing in any regular text as well like this office mac chris date I can t believe it s already week V of Y here in the Z time zone But what do you expect on a 2A at 1 3M p BONUS CHAPTER THE UNIX CRASH COURSE 20 Useful Unix Utilities 43 20 Useful Unix Utilities I can t believe it s already week 25 of 2012 here in the PDT time zone But what do you expect on a Saturday at 3 42 PM Note Be careful about using date with sudo If you do and accidentally forget the leading you reset your Mac s built in clock
78. s your command line activity fills the Terminal window with text older lines at the top disappear from view So that you can get back to these previous lines for viewing copying or printing Terminal offers a scrollback buffer which sets aside a certain amount of memory and adds a scroll bar so that you can do so Terminal stores the data in this buffer very efficiently so you should have no problem keeping this at its default unlimited setting However if you do get the crazy urge to display all one million lines from the manpages you just might run out of memory if you don t set a limit Note And how would you do that By running this command of course find cat etc manpaths type f exec man P cat Shell Startup Enter a command here for example cal y and each time you open a new window you ll see its output and then get a new prompt If you just want the output without a new prompt turn off Run inside shell When the shell exits When youre finished fooling around in Terminal you end your session either by closing the window or more properly by typing exit or pressing Control D at the prompt The When the Shell Exits setting determines what happens when you do that Prompt before closing Shell commands can take some time to complete In some cases when you attempt to close a Terminal window before its work is finished Terminal asks you if you re sure you want to cancel the process an
79. server Perhaps best of all since you can run find with sudo you can look for files existing anywhere on your hard disk regardless of directory permission settings To find all the files in your home directory with Bolinas in their names for example you would use this command find name Bolinas Or to ignore capitalization find iname Bolinas And this command searches for all the locked files in your home directory find flags uchg mdfind If you have a soft spot in your heart for Spotlight youll be happy to see the mdfind command in Terminal It performs the same kinds of searches finding by metadata like music genre or exposure data for photos To find all reggae songs for example try BONUS CHAPTER THE UNIX CRASH COURSE 20 Useful Unix Utilities 45 20 Useful Unix Utilities 46 mdfind kMDItemMusicalGenre Reggae To find all photos you shot with the flash on mdfind kMDItemFlashOnOff 1 The mdls command reveals all the metadata for a particular file like the IMG_3033 jpg picture in this example MacChris Photos chris mdls IMG_3033 cr2 kMDItemAcquisitionMake Canon kMDItemAcquisitionModel Canon EOS 40D kMDItemAperture 4 kMDItemBitsPerSample 64 kMDItemColorSpace RGB kMDItemContentCreationDate 2010 12 19 18 50 30 0000 kMDItemContentModificationDate 2010 12 19 18 50 31 0000 kMDItemContentType com canon
80. t For the purpose of this introduc tion to rm double check that administration privileges are indeed turned off for your account To use this command just type rm a space and the exact name of the file you want to delete from the working directory To remove the file practice txt you created with the touch command for example yowd just type rm practice txt To remove a directory and everything in it add the r flag like this rm r PracticeFolder If youre feeling particularly powerful and you like taking risks you can even use wildcards with the rm command Now many experienced Unix users make it a rule to never use rm with wildcards while logged in as an administrator because one false keystroke can wipe out everything in a directory But here for study purposes only is the atomic bomb of command lines the one that deletes everything in the working directory rm rf Tip Be doubly cautious when using wildcards in rm command lines and triply cautious when using them while logged in as an administrator If you re using Time Machine you have a safety net of course But why tempt fate Just after the letters rm you can insert options like these BONUS CHAPTER THE UNIX CRASH COURSE Working with Files and Directories 19 Working with Files and Directories 20 d deletes any empty directories it finds in addition to files Otherwise empty directories trigger an error message f atte
81. t matches a specified pattern It can pass on the processed result to another program file or the command line itself You specify the text pattern you want grep to search using a notation called regular expressions For example the regular expression dis ck searches for either disk or disc Another example To search for lines in a file containing the addresses from 200 to 299 Redwood Way you could tell grep that you re looking for lt 2 0 9 0 9 Redwood Way One terrific thing about grep is that its search material can be part of any file especially plain text files The text files on your Mac include HTML files log files and possibly juiciest of all your email mailbox files Using grep for example you could search all your Mail files for messages matching certain criteria with great efficiency and even finer control than with Spotlight find With Spotlight on the scene you might wonder why you would need to use the Unix find command Well for one find takes file searching to a whole new level For example you can find files based on their permissions owner name flag settings and of course any kind of name pattern you can think of using regular expressions Also like with most other Unix commands you can pipe the find command s list of found files straight into another program for further processing You might do this to change their names convert them to other formats or even upload them to a network
82. t letter or two and then press Tab again BONUS CHAPTER THE UNIX CRASH COURSE Navigating in Unix 11 Navigating in Unix 12 Using the history You may find yourself at some point needing to run a previously entered command but dreading the prospect of re entering the whole command Retyping a command however is never necessary Terminal or rather the shell it s running remembers the last 500 commands you entered At any prompt instead of typing just press the T or keys to walk through the various commands in the shell s memory They flicker by one at a time at the prompt right there on the same line ann Shorts bash iw 18 e Figure 4 Ta lt a The double dot tells Unix a EEEa T A ir malas Manag to switch its attention Meera Caries Meriani Trailers 2 S office amiTeailari darii cf Mokeetay to the Movies directory Oliicc mad i Sharks ghrisg walking upward through the directory tree the rest 5 tells it to walk down the Movies directory into the Shorts directory Note that s B the prompt always identi damd pa er Oa ar fies the current working khong Documenti Dearvari haat directory Edy ale Lia Movies Music Picbures ADL alli Movies Shorts Tralee a Fiii Mir 1 Firei Mari d Wildcards Wildcards are special characters that represent other characters and they re huge timesavers The most popular wildcard is the asterisk which means any text can go her
83. that are invisible by the Unix definition still don t show up You can use one of the s command s flags however to force even Unix invisible files to appear Just add the a flag In other words type this Is a Now when you press Return you might see something like this Desktop Music Documents Pictures CFUserTextEncoding Downloads Public DS_ Store Library Trash Movies F As you see the names of invisible Unix files all begin with a period Unix folk call them dot files But are these files or folders To find out use Is with the F option capitalization counts like this ls aF Yowre shown something like this AYA Desktop Music acl Documents Pictures CFUserTextEncoding Downloads Public DS_Store Library Trash Movies The names of the items themselves haven t changed but the F flag makes slashes appear on directory folder names This example shows that in your home direc tory there are 12 other directories and two files G Here s a fascinating flag that makes ls display color coded results blue for di rectories red for programs normal black on white type for documents and so on R The R flag produces a recursive listing one that shows you the directories within the directories in the list Listing all of the home directory could take several pages but if you type ls R Movies for example you might get something like this Bad Reviews doc Old Tahoe Footage 2 Picnic Movie 2 Revie
84. ts There s one more one that wields ultimate power one person who can do anything to any file anywhere This person is called the superuser Unix fans speak of the superuser account also called the root account in hushed tones because it offers absolutely unre stricted power The root account holder can move delete rename or otherwise mangle any file on the machine no matter what folder it s in One wrong move or one malicious hacker who manages to seize the root account and you ve got yourself a 2 000 doorstop That s why Mac OS X s root account is completely hidden Truth is you can enjoy most rootlike powers without actually turning on the root account Here are some of the things the root account holder can do and the ways you can do them without ducking into a phone booth to become the superuser See crucial system files that are ordinarily invisible Of course you can also see them easily by using the freeware program TinkerTool You can also use the Terminal program described in this chapter Peek into other account holders folders or even trash them You don t have to be the superuser to do this you just have to be an administrator who s smart enough to use the Get Info command as described on page 96 Use powerful Unix system commands Some of the Unix commands you can issue in Mac OS X require superuser powers As noted in this chapter however there s a simple command the sudo command that
85. ure 7 To move on to the next man screen press the space bar To go back press the t key or the b key To close the manual and return to a prompt press q You can also search for a certain ye te phrase by typing a to seeds produce the find what Tits prompt thereafter type n to find the next occur rence Tenis it BO Other Unix Help Sometimes Terminal shoves a little bit of user manual right under your nose when it thinks you re having trouble For example if you use the mkdir command without specifying a pathname mkdir interrupts the proceedings by displaying its own syn opsis as a friendly reminder subtext Um this is how you re supposed to use me like this usage mkdir pv m mode directory MAC OS X THE MISSING MANUAL Terminal Preferences If you spend endless hours staring at the Terminal screen as most Unix junkies do you ll eventually be grateful for the preference settings that let you control how Terminal looks and acts In fact Terminal lets you manage your preferences in an ingenious way Instead of having a single set of options saved as with other applications Terminal manages your options as named settings groups allowing you to quickly apply different settings to different windows at any time using the Inspector window Shell gt Show Inspector You can also save the layout of entire groups of windows each with their own settings in effect into a sing
86. vealing the working directory s path a list of folders in folders sepa rated by slashes that specifies a folder s location on your hard drive Users chris Movies pinpoints the Movies folder in Chris s Home folder which like all Home folders is in the Users directory Tip Remember that capitalization counts in Unix Command names are almost always all lowercase like cal and pwd But when you type the names of folders be sure to capitalize correctly Is List or What s in here The Is command short for list makes Terminal type out the names of all the files and folders in the folder you re in that is your working directory You can try it right now Just type s and then press Return Terminal responds by showing you the names of the files and folders inside in a list like this Desktop Downloads Movies Pictures Documents Library Music Public In other words you see a list of the icons that in the Finder yowd see in your Home folder Note Terminal respects the limits of the various Mac OS X accounts Chapter 12 In other words a Standard or Administrator account holder isn t generally allowed to peek further into someone else s Home folder If you try you ll be told Permission denied You can also make Terminal list what s in any other directory one that s not the working directory just by adding its pathname as an argument Arguments are extra pieces of information after t
87. wn brain though you can pronounce it however you like Note Only Administrator account holders can use the sudo command If you have the root account or can simulate one using sudo you can override any permissions settings including the ones that prevent you from changing things in the Applications directory like iChat Now youre ready to change the permissions of that infernal iChat application file To use sudo you must preface an entire command line with sudo and a space Type this sudo chmod o x Applications iChat app Contents MacOS iChat Taken slowly this command breaks down as follows sudo Give me the power to do whatever I want chmod Change the file mode o x in this way remove execute permission for others Applications iChat app Contents MacOS iChat from the file called iChat which is inside the Applications iChat app Contents MacOS folder The first time you run sudo youre treated to a stern talking to that means business MAC OS X THE MISSING MANUAL Warning Improper use of the sudo command could lead to data loss or the deletion of important system files Please double check your typing when using sudo Type man sudo for more information To proceed enter your password or type Ctrl C to abort In other words sudo is a powerful tool that lets you tromp unfettered across delicate parts of Mac OS X so you should proce
88. ws doc Old Tahoe Footage 2 Tahoe 1 mov Tahoe 3 mov Tahoe Project File Tahoe 2 mov Tahoe 4 mov Picnic Movie 2 Icon Media Picnic Movie 2 Project Picnic Movie 2 Media Picnic Movie 1 Picnic Movie 3 Picnic Movie 5 Picnic Movie 2 Picnic Movie 4 Picnic Movie 6 In other words you ve got two subdirectories here called Old Tahoe Footage 2 and Picnic Movie 2 which itself contains a Media directory BONUS CHAPTER THE UNIX CRASH COURSE Navigating in Unix Navigating in Unix 10 Tip As you can tell by the ca and s examples Unix commands are very short They re often just two letter commands and an impressive number of those use alternate hands Is cp rm and so on The reason has partly to do with conserving the limited memory of early computers and partly to do with efficiency Most programmers would just as soon type as little as possible to get things done User friendly it ain t but as you type these commands repeatedly over the months you ll eventually be grateful for the keystroke savings cd Change Directory or Let Me See Another Folder Now you know how to find out what directory youre in and how to see what s in it all without double clicking any icons That s great information but it s just informa tion How do you do something in your command line Finder like switching to a different directory To change your working directory use the cd command followed by the path of the
89. y of an erased file almost impossible More than you ever wanted to know is at www cs auckland ac nz pgut001 pubs secure_del html The bottom line To make sure no one ever ever reads that poem you typed out for your cat one lonely bleary eyed evening type srm My Twinkie doc That will be the end of it and neither the CIA nor software like DataRescue will ever know what it was echo A Final Check You can make rm or srm less risky by prefacing it with the echo command It makes Terminal type out the command a second time this time with a handy list of exactly what youre about to obliterate If you ve used wildcards you see the names of the files that will be affected by the character If you type echo rm r for example which without the echo part would normally mean delete everything in this directory you might see a list like this rm r Reviews doc Tahoe Footage Picnic Movie Contract doc Once you ve reviewed the list and approved what Terminal is about to do then you can retype the command without the echo portion MAC OS X THE MISSING MANUAL Note The rm command doesn t work on file or directory names that begin with a hyphen To delete these items from your working directory preface their names with a dot slash like this rm Recipes doc Unix Help Mac OS X comes with over 1 400 Unix programs like the ones described in this chapter How are you supposed to learn what they all do
90. y programs are listed first If your Mac ever seems to be sluggish checking top u to see what s tying things up is a good instinct xattr extended attributes The xattr command lets you see and manage the extended attributes EAs of your files the invisible metadata that describes all kinds of characteristics of every file from the exposure of a digital camera shot to the tempo of a song in iTunes Chapter 3 has much more on metadata and searching for it Running xattr lists any EAs in your working directory If you ran it in your Downloads folder the command might look like this MacChris Downloads chris xattr GoogleEarthMac dmg com apple diskimages fsck GoogleEarthMac dmg com apple diskimages recentcksum GoogleEarthMac dmg com apple metadata kMDItemWhereFroms GoogleEarthMac dmg com apple quarantine MacPorts 2 0 2 10 7 Lion dmg com apple diskimages fsck MacPorts 2 0 2 10 7 Lion dmg com apple diskimages recentcksum MacPorts 2 0 2 10 7 Lion dmg com apple metadata kMDItemDownloadedDate MacPorts 2 0 2 10 7 Lion dmg com apple BONUS CHAPTER THE UNIX CRASH COURSE 20 Useful Unix Utilities 41 20 Useful Unix Utilities 42 metadata kMDItemWhereFroms MacPorts 2 0 2 10 7 Lion dmg com apple quarantine Viscosity1 3 4 dmg com apple metadata kMDItemDownloadedDate Viscosity1 3 4 dmg com apple metadata kMDItemWhereFroms Viscosity1 3 4 dmg com apple quarantine Only three files are listed but each
91. zes the letter following the insertion point Esc U Changes the next word or word section to all uppercase letters Esc L Changes the next word or word section to all lowercase letters Working with Files and Directories The previous pages show you how to navigate your directories using Unix commands Just perusing your directories isn t particularly productive however This section shows you how to do something with the files you see listed copy move create and delete directories and files Tip You re entering Serious Power territory where it s theoretically possible to delete a whole directory with a single typo As a precaution consider working through this section with administrator privileges turned off for your account so that you won t be able to change anything outside your home directory or to be really safe create a new test account just for this exercise so even your personal files won t be at risk cp Copy Using the Unix command cp you can copy and rename a file in one move Try that in the Finder The basic command goes like this cp path1 path2 where the path placeholders rep resent the original file and the copy respectively Copying in place To duplicate a file called Thesis doc you would type cp Thesis doc Thesis2 doc That s just one space between the names You don t have to call the copy Thesis2 you could call it anything you like The point is that you wind up with two identical files

The Unix Crash Course - How to Example Code

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