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Mac OS X Command Line Tutorial
While much of OS X is graphical, much of its power still resides with the command line tools available through the Terminal.
OS X is based on FreeBSD, a UNIX-compliant operating system.
This means many powerful UNIX tools are available to Mac users:
- Apache
- network utilities
- compilers
Over 1000 commands!
The OS X filesystem is a hierarchy, or tree, of folders and files,
At the top is a folder called the root directory.
Below the root directory are system folders that you might recognize:
- Applications
- Users
- Volumes
- Library
- System
- bin
- usr
- etc
Each directory contains subdirectories. Subdirectory names are separated by forward slashes (Windows/DOS uses backslashes).
Located in /Applications/Utilities.
The Terminal is an application that runs commands.
Opening the terminal presents the following:
Last login: Fri Sep 7 09:28:20 on ttys003
Cepeda:~ fonnescj$
This is output from a special program that runs inside the terminal called the shell. The shell does four things:
- displays a prompt for recieving commands
- reads your and interprets commands
- runs commands, locating any necessary programs
- prints the output of the command, if any
First line is date and time of last login, plus the type of terminal being used.
Second line shows the name of your machine, followed by your user name and a prompt ($).
You can open a new window with cmd-N or a new tab with cmd-T.
The prompt indicates that you can type a command.
Try using echo:
$ echo Hello $LOGNAME!
Hello fonnescj!
Most commands use the following syntax:
$ command -option1 -option2 ... argument1 argument2 ...
Arguments are additional information required for some commands. Options are settings that affect the behavior of the program, and are usually preceded by one or two dashes.
Unlike DOS/Windows, UNIX shells are usually case-sensitive.
cal: displays a calendar
$ cal sep 2012
September 2012
Su Mo Tu We Th Fr Sa
1
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
ls: lists contents of a folder
$ ls /Volumes
Backup Macintosh HD MobileBackups
If you wanted to list all of the files with a .txt extension, you can use the wildcard symbol (*):
$ ls *txt
oilspill.txt oilspill_count.txt values.txt
wc: count the number of lines, words, bytes
$ wc oilspill.txt
0 1986 25134 oilspill.txt
Let's combine some commands, using the pipe | symbol
$ ls $HOME/Documents | wc -l
13
df: display free disk space
$ df -h /
Filesystem Size Used Avail Capacity iused ifree %iused Mounted on
/dev/disk0s2 233Gi 144Gi 88Gi 63% 37913533 23155907 62% /
top: show the processes running on your system
To print a static list of all running processes, use ps:
$ ps ax
PID TT STAT TIME COMMAND
1 ?? Ss 2:56.64 /sbin/launchd
11 ?? Ss 0:08.43 /usr/libexec/UserEventAgent (System)
12 ?? Ss 0:16.38 /usr/libexec/kextd
14 ?? Ss 0:27.99 /usr/sbin/notifyd
15 ?? Ss 0:41.63 /usr/sbin/securityd -i
16 ?? Ss 0:05.37 /usr/sbin/diskarbitrationd
17 ?? Ss 5:05.07 /usr/libexec/configd
...
uptime: show how long your computer has been running
$ uptime
10:41 up 3 days, 23:48, 5 users, load averages: 1.16 1.00 0.94
This includes current time, uptime, number of users, and load averages for the past 1, 5, 15 min.
ipconfig: view IP configuration
$ ipconfig getifaddr en0
10.43.245.108
This shows the ethernet IP address.
curl: downloads a file from the internet
$ curl -O https://dl.dropbox.com/u/233041/simple.py
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 1927 100 1927 0 0 2363 0 --:--:-- --:--:-- --:--:-- 4700
mv: moves a file from one location to another
$ mv simple.py ~/Desktop
clear: clears the terminal
open: opens files and directories using their default applications
$ open ~/Documents
sudo: allows commands to be run as another user, usually as an administrator
$ sudo softwareupdate -l
Software Update Tool
Copyright 2002-2010 Apple
Software Update found the following new or updated software:
* JavaForOSX-1.0
Java for OS X 2012-005 (1.0), 65288K [recommended]
more: examine the contents of a file
$ more values.txt
27,<2,4,-0.27,-0.13
27,2to4,5,-0.35,-0.31
27,5to7,3,-0.46,-0.31
27,8to11,3,-0.27,-0.33
27,12to18,5,-0.57,-0.51
locate: find filenames
$ locate .bash
/Users/fonnescj/.bash_history
/Users/fonnescj/.bash_profile
/Users/fonnescj/.bashrc
/Users/fonnescj/dotfiles/.bash_profile
/Users/fonnescj/dotfiles/.bashrc
/usr/local/Cellar/ack/1.96/etc/bash_completion.d/ack.bash_completion.sh
/usr/local/Cellar/git/1.7.11.1/etc/bash_completion.d/git-completion.bash
/usr/local/Cellar/git/1.7.12/etc/bash_completion.d/git-completion.bash
/usr/local/Cellar/git/1.7.9.2/etc/bash_completion.d/git-completion.bash
/usr/local/Cellar/hub/1.10.2/etc/bash_completion.d/hub.bash_completion.sh
/usr/local/etc/bash_completion.d/ack.bash_completion.sh
/usr/local/etc/bash_completion.d/git-completion.bash
/usr/local/etc/bash_completion.d/hub.bash_completion.sh
/usr/local/texlive/2011/texmf-dist/scripts/changes/delcmdchanges.bash
/usr/share/emacs/22.1/etc/emacs.bash
/usr/share/git-core/git-completion.bash
kill: terminate a process
Some of the more commonly used signals:
1 HUP (hang up)
2 INT (interrupt)
3 QUIT (quit)
6 ABRT (abort)
9 KILL (non-catchable, non-ignorable kill)
14 ALRM (alarm clock)
15 TERM (software termination signal)
Let's kill our browser!
$ ps ax | grep Safari
24748 ?? R 0:04.82 /Applications/Safari.app/Contents/MacOS/Safari -psn_0_18084158
$ kill -9 24748
By default, when you open a terminal the shell is located in your home directory. You can always check what the present working directory is by using pwd:
$ pwd
/Users/fonnescj
Notice the leading slash before Users; this shows that this is an absolute path. A relative path (i.e. relative to the working directory) has no forward slash:
$ ls Library
Accounts Fonts Preferences
Address Book Plug-Ins Fonts Disabled Printers
Application Scripts Frameworks PubSub
Application Support Google R
...
This is different than:
$ ls /Library
Application Support Graphics QuickTime
Audio Image Capture Receipts
Automator Input Methods Ruby
There are two important shortcuts for relative paths:
- '.' refers to the current directory
- '..' refers to the parent directory
Thus,
$ ls ..
Shared fonnescj
You can move from one directory to another using the cd (change directory) command:
$ cd Library/Application\ Support
$ pwd
/Users/fonnescj/Library/Application Support
If you would rather not type the entire directory name, clicking the tab button will attempt to auto-complete it, as long as you have typed enough letters to uniquely identify a folder.
To add an arbitrary appendix to a filename, try:
mv file{, =old}
For example,
$ mv values.txt{,.old}
$ ls val*
values.txt.old
Shut down or restart your computer by using shutdown (the -r flag restarts).
sudo shutdown -r now
Use the !$ argument to repeat the argument from the previous command:
$ ls /usr/local/bin
GraphicsMagick++-config lconvert
GraphicsMagick-config lefty
GraphicsMagickWand-config libpng-config
R libpng15-config
Rscript list_instances
...
$ cd !$
cd /usr/local/bin
Typing ctrl-r will bring up a search tool that scans your command history for letters that you type:
(reverse-i-search)`c': cd /usr/local/bin
Typing crtl-r again will get the previous instance.
say will read files out loud through your computer's speakers. If we send a text file to it, your Mac will read it out loud:
$ cat values.txt | say