# A-Z Index of the Apple OS X command line #

### A ###
**alias**								Create an alias •
**alloc**								List used and free memory
**apropos**							Search the whatis database for strings
**asr**									Apple Software Restore
**awk**									Find and Replace text within file(s)**

### B ###
**basename**						Convert a full pathname to just a filename
**bash**								Bourne-Again SHell
**bg**									Send to background •
**bind**								Display readline key and function bindings •
**bless**								Set volume bootability and startup disk options
**break**								Exit from a For, While, Until or Select loop •
**builtin**							Execute a shell builtin •
**bzip2**								Compress or decompress files**

### C ###
**cal**									Display a calendar
**calendar**						Reminder Service
**caller**							Return the context of a subroutine call •
**case**								Conditionally perform a command •
**cat**									Concatenate and print (display) the content of files
**cd**									Change Directory •
**chflags**							Change a file or folder's flags
**chgrp**								Change group ownership
**chmod**								Change access permissions
**chown**								Change file owner and group
**chroot**							Run a command with a different root directory
**cksum**								Print CRC checksum and byte counts
**clear**								Clear terminal screen
**cmp**									Compare two files
**comm**								Compare two sorted files line by line
**command**							Run a command (not a function) •
**complete**						Edit a command completion [word/pattern/list] •
**continue**						Resume the next iteration of a loop •
**cp**									Copy one or more files to another location
**cron**								Daemon to execute scheduled commands
**crontab**							Schedule a command to run at a later date/time
**csplit**							Split a file into context-determined pieces
**curl**								Transfer data from or to a server
**cut**									Divide a file into several parts

### D ###
**date**								Display or change the date & time
**dc**									Desk Calculator
**dd**									Convert and copy a file, clone disks
**declare**							Declare variable & set attributes •
**defaults**						Set preferences, show hidden files
**df**									Display free disk space
**diff**								Display the differences between two files
**diff3**								Show differences among three files
**dig**									DNS lookup
**dirname**							Convert a full pathname to just a path
**dirs**								Display list of remembered directories •
**diskutil**						Disk utilities - Format, Verify, Repair
**disown**							Unbind a job from the current login session •
**ditto**								Copy files and folders
**dot_clean**						Remove dot-underscore files
**drutil**							Interact with CD/DVD burners
**dscacheutil**					Query or flush the Directory Service/DNS cache
**dseditgroup**					Edit, create, manipulate, or delete groups
**dsenableroot** 				Enable root access
**dsmemberutil** 				View user and groups rights
**dscl**								Directory Service command line utility
**du**									Estimate file space usage

### E ###
**echo**								Display text on screen •
**ed**									A line-oriented text editor (edlin)
**enable**							Enable and disable builtin shell commands •
**env**									List or Set environment variables
**eval**								Evaluate several commands/arguments •
**exec**								Execute a command •
**exit**								Exit the shell •
**expand**							Convert tabs to spaces
**expect**							Programmed dialogue with interactive programs
**export**							Set an environment variable •
**expr**								Evaluate expressions**

### F ###
**false**								Do nothing, unsuccessfully
**fc**									Fix command (history)
**fdisk**								Partition table manipulator for Darwin UFS/HFS/DOS
**fg**									Send job to foreground •
**file**								Determine file type
**find**								Search for files that meet a desired criteria
**fmt**									Reformat paragraph text
**fold**								Wrap text to fit a specified width
**for**									Loop command •
**fsck**								Filesystem consistency check and repair
**fsaclctl**						Filesystem enable/disable ACL support
**fs_usage**						Filesystem usage (process/pathname)
**ftp**									Internet file transfer program**

### G ###
**GetFileInfo** 				Get attributes of HFS+ files
**getopt**							Parse positional parameters
**getopts**							Parse positional parameters •
**goto**								Jump to label and continue execution
**grep**								Search file(s) for lines that match a given pattern
**groups**							Print group names a user is in
**gzip**								Compress or decompress files

### H ###
**halt**								Stop and restart the operating system
**hash**								Refresh the cached/remembered location of commands •
**head**								Display the first lines of a file
**hdiutil**							Manipulate iso disk images
**history**							Command History •
**hostname**						Print or set system name

### I ###
**iconv**								Convert the character set of a file
**id**									Print user and group names/id's
**if**									Conditionally perform a command •
**ifconfig**						Configure network interface parameters
**ipconfig**						View and control IP configuration state
**info**								Help info
**install**							Copy files and set attributes

### J ###
**jobs**								List active jobs •
**join**								Join lines on a common field

### K ###
**kextfind**						List kernel extensions
**kickstart** 					Configure Apple Remote Desktop
**kill**								Stop a process from running

### L ###
**l**										List files in long format (ls -l)
**last**								Indicate last logins of users and ttys
**launchctl** 					Load or unload daemons/agents
**ll**									List files in long format, showing invisible files (ls -la)
**less**								Display output one screen at a time
**let**									Evaluate expression •
**lipo**								Convert a universal binary
**ln**									Make links between files (hard links, symbolic links)
**local**								Set a local (function) variable •
**locate**							Find files
**logname**							Print current login name
**login**								Log into the computer
**logout**							Exit a login shell (bye) •
**look**								Display lines beginning with a given string
**lpr**									Print files
**lprm**								Remove jobs from the print queue
**lpstat**							Printer status information
**ls**									List information about file(s)
**lsregister**					Reset the Launch Services database
**lsbom**								List a bill of materials file
**lsof**								List open files

### M ###
**man**									Help manual
**mdfind**							Spotlight search
**mdutil**							Manage Spotlight metadata store
**mkdir**								Create new folder(s)
**mkfifo**							Make FIFOs (named pipes)
**more**								Display output one screen at a time
**mount**								Mount a file system
**mv**									Move or rename files or directories

### N ###
**nano**								Simple text editor
**net**									Manage network resources
**netstat**							Show network status
**networksetup** 				Network and System Preferences
**nice**								Set the priority of a command
**nohup**								Run a command immune to hangups
**ntfs.util** 					NTFS file system utility

### O ###
**onintr**							Control the action of a shell interrupt
**open**								Open a file/folder/URL/Application
**opensnoop**						Snoop file opens as they occur
**osacompile**					Compile Applescript
**osascript**						Execute AppleScript

### P ###
**passwd**							Modify a user password
**paste**								Merge lines of files
**pbcopy**							Copy data to the clipboard
**pbpaste**							Paste data from the Clipboard
**ping**								Test a network connection
**pkgutil**							Query and manipulate installed packages
**plutil**							Property list utility
**pmset**								Power Management settings
**popd**								Restore the previous value of the current directory •
**pr**									Convert text files for printing
**printenv**						List environment variables
**printf**							Format and print data •
**ps**									Process status
**pushd**								Save and then change the current directory
**pwd**									Print Working Directory •

### Q ###
**quota**								Display disk usage and limits**

### R ###
**rcp**									Copy files between machines
**read**								Read one line from standard input •
**readonly**						Mark a variable or function as read-only •
**reboot**							Stop and restart the system
**return**							Exit a function •
**rev**									Reverse lines of a file
**rm**									Remove files
**rmdir**								Remove folder(s)
**rpm**									Remote Package Manager
**rsync**								Remote file copy - Sync file tree (also RsyncX)

### S ###
**say**									Convert text to audible speech
**screen**							Multiplex terminal, run remote shells via ssh
**screencapture** 			Capture screen image to file or disk
**scutil**							Manage system configuration parameters
**sdiff**								Merge two files interactively
**security**						Administer Keychains, keys, certificates and the Security framework
**sed**									Stream Editor
**select**							Generate a list of items •
**set**									Set a shell variable = value •
**setfile**							Set attributes of HFS+ files
**shasum**							Print or Check SHA Checksums
**shift**								Shift positional parameters •
**shopt**								Set shell options •
**shutdown**						Shutdown or restart OS X
**sips**								Scriptable image processing system
**sleep**								Delay for a specified time
**softwareupdate** 			System software update tool
**sort**								Sort text files
**source**							Execute commands from a file •
**split**								Split a file into fixed-size pieces
**stat**								Display the status of a file
**stop**								Stop a job or process
**su**									Substitute user identity
**sudo**								Execute a command as another user
**sum**									Print a checksum for a file
**suspend**							Suspend execution of this shell •
**sw_vers**							Print Mac OS X operating system version
**system_profiler**			Report system configuration
**systemsetup** 				Computer and display system settings

### T ###
**tail**								Output the last part of files
**tar**									Tape ARchiver
**tcpdump**							Dump traffic on a network
**tee**									Redirect output to multiple files
**test**								Condition evaluation •
**textutil**						Manipulate text files in various formats (Doc,html,rtf)
**time**								Measure Program Resource Use
**times**								Print shell & shell process times •
**tmutil**							Time Machine utility
**top**									Display process information
**touch**								Change file timestamps
**tr**									Translate, squeeze, and/or delete characters
**trap**								Execute a command when the shell receives a signal •
**traceroute**					Trace Route to Host
**true**								Do nothing, successfully
**tty**									Print filename of terminal on stdin
**type**								Describe a command •

### U ###
**ufs.util**						Mount/unmount UFS file system
**ulimit**							Limit the use of system-wide resources •
**umask**								Users file creation mask
**umount**							Unmount a device
**unalias**							Remove an alias •
**uname**								Print system information
**unexpand**						Convert spaces to tabs
**uniq**								Uniquify files
**units**								Convert units from one scale to another
**unset**								Remove variable or function names •
**until**								Loop command •
**uptime**							Show how long system has been running
**users**								Print login names of users currently logged in
**uuencode**						Encode a binary file** 
**uudecode**						Decode a file created by uuencode
**uuidgen**							Generate a Unique ID (UUID/GUID)
**uucp**								Unix to Unix copy

### V ###
**vi**									Text Editor

### W ###
**wait**								Wait for a process to complete •
**wc**									Print byte, word, and line counts
**whatis**							Search the whatis database for complete words
**where**								Report all known instances of a command
**which**								Locate a program file in the user's path
**while**								Loop command •
**who**									Print all usernames currently logged on
**whoami**							Print the current user id and name (`id -un')
**write**								Send a message to another user**

### X ###
**xargs**								Execute utility - passing arguments
**yes**									Print a string until interrupted
**zip**									Package and compress (archive) files.
**!!**									Run the last command again

[Commands marked • are bash *built-in* commands]