View source for Basic commands in Linux

[[w:Unix-like|Unix-like]] [[operating system]]s require a working knowledge of several basic commands. [[w:Unix|Unix®]], [[w:Linux|Linux]], [[w:Berkeley Software Distribution|BSD]] and such use a ubiquitous set of these based on the [[w:Single UNIX Specification|Single UNIX Specification]]. Learning to operate a [[command line interface]] is a key skill in learning [[Linux]] and [[BSD]].
== Basic commands ==
{| class=" wikitable sortable"
|+ IEEE Std 1003.1-2001 utilities
|-
!style="width:10em;"| Name
!style="width:15em;"| Category 
!style=""| Description
!style="width:5em;;"| First appeared
|-
| [[w:admin (Unix)|admin]]
| [[w:Source Code Control System|SCCS]]
| Create and administer [[w:Source Code Control System|SCCS]] files
| 
|-
| [[w:Alias (command)|alias]]
| Misc
| Define or display aliases
| 
|-
| [[w:ar (Unix)|ar]]
| Misc
| Create and maintain [[w:Library (computing)|library]] archives
| 
|-
| [[w:asa (Unix)|asa]]
| Text Processing
| Interpret carriage-control characters
| 
|-
| [[w:at (Unix)|at]]
| Process Management
| Execute commands at a later time
| Version 7 AT&T UNIX
|-
| [[w:AWK (programming language)|awk]]
| Text processing
| Pattern scanning and processing language
| Version 7 AT&T UNIX
|-
| [[w:basename|basename]]
| Filesystem
| Return non-directory portion of a pathname
| 
|-
| [[w:batch (Unix)|batch]]
| Process Management
| Schedule commands to be executed in a batch queue
| 
|-
| [[w:bc programming language|bc]]
| Misc
| [[w:Arbitrary-precision arithmetic|Arbitrary-precision arithmetic]] language
| 
|-
| [[w:bg (Unix)|bg]]
| Process Management
| Run jobs in the background
| 
|-
| [[w:break (Unix)|break]]
| Shell programming
| Exit from [[w:for loop|for]], [[w:while loop|while]], or [[w:until|until]] [[w:Control flow#Loops|loop]]
| 
|-
| [[w:c99_(Unix)|c99]]
| C Programming
| [[w:compiler|Compile]] standard [[w:C (programming language)|C]] programs
| 
|-
| [[w:cal (Unix)|cal]]
| Misc
| Print a calendar
| Version 5 AT&T UNIX
|-
| [[w:cat (Unix)|cat]]
| Filesystem
| Concatenate and print files
| Version 1 AT&T UNIX
|-
| [[w:cd (command)|cd]]
| Filesystem
| Change the working directory
| 
|-
| [[w:cflow|cflow]]
| C Programming
| Generate a C-language [[w:flowgraph|flowgraph]]
| 
|-
| [[w:chgrp|chgrp]]
| Filesystem
| Change the file group ownership
| 
|-
| [[w:chmod|chmod]]
| Filesystem
| Change the file modes/attributes/permissions
| Version 1 AT&T UNIX
|-
| [[w:chown|chown]]
| Filesystem
| Change the file ownership
| Version 1 AT&T UNIX
|- 
| [[w:cksum|cksum]]
| Filesystem
| Write file [[w:checksums|checksums]] and sizes
| 4.4BSD
|-
| [[w:cmp (Unix)|cmp]]
| Filesystem
| Compare two files
| Version 1 AT&T UNIX
|-
| [[w:comm|comm]]
| Text Processing
| Select or reject lines common to two files
| Version 4 AT&T UNIX
|-
| [[w:command (Unix)|command]]
| Shell Programming
| Execute a simple command
| 
|-
| [[w:compress|compress]]
| Filesystem
| Compress data
| 4.3BSD
|-
| [[w:continue (Unix)|continue]]
| Shell programming
| Continue [[w:for_loop|for]], [[w:while_loop|while]], or [[w:until|until]] [[w:Control_flow#Loops|loop]]
| 
|-
| [[w:cp (Unix)|cp]]
| Filesystem
| Copy files
| Version 1 AT&T UNIX
|-
| [[w:crontab|crontab]]
| Misc
| Schedule periodic background work
| 
|-
| [[w:csplit|csplit]]
| Text Processing
| Split files based on context
| PWB UNIX
|-
| [[w:ctags|ctags]]
| C Programming
| Create a tags file
| 3.0BSD
|-
| [[w:cut (Unix)|cut]]
| Shell Programming
| Cut out selected fields of each line of a file
| 
|-
| [[w:cxref|cxref]]
| C Programming
| Generate a [[w:C (programming language)|C-language]] program cross-reference table
| 
|-
| [[w:date (Unix)|date]]
| Misc
| Write the date and time
| Version 1 AT&T UNIX
|-
| [[w:dd (Unix)|dd]]
| Filesystem
| Convert and copy a file
| 
|-
| [[w:delta (Unix)|delta]]
| SCCS
| Make a delta (change) to an SCCS file
| 
|-
| [[w:df (Unix)|df]]
| Filesystem
| Report free disk space
| Version 1 AT&T UNIX
|-
| [[w:diff|diff]]
| Text processing
| Compare two files
| 
|-
| [[w:dirname|dirname]]
| Filesystem
| Return the directory portion of a pathname
| 
|-
| [[w:dot (Unix)|dot]]
| Shell programming
| Execute commands in the current environment
| 
|-
| [[w:du (Unix)|du]]
| Filesystem
| Estimate file space usage
| Version 1 AT&T UNIX
|-
| [[w:echo (command)|echo]]
| Shell programming
| Write arguments to standard output
| 
|-
| [[w:ed (text editor)|ed]]
| Text processing
| The standard text editor
| Version 1 AT&T UNIX
|-
| [[w:env (shell)|env]]
| Misc
| Set the environment for command invocation
| 
|-
| [[w:eval]]
| Shell programming
| Construct command by concatenating arguments
| 
|-
| [[w:ex (editor)|ex]]
| Text processing
| Text editor
| BSD
|-
| [[w:exec (operating system)|exec]]
| Shell programming
| Execute commands and open, close, or copy [[w:file descriptors|file descriptors]]
| 
|-
| [[w:exit (command)|exit]]
| Shell programming
| Cause the shell to exit
| 
|-
| [[w:expand (Unix)|expand]]
| Text Processing
| Convert tabs to spaces
| 3.0BSD
|-
| [[w:Environment variable#UNIX|export]]
| Misc
| Set the export attribute for variables
| 
|-
| [[w:expr|expr]]
| Shell Programming
| Evaluate arguments as an expression
| 
|-
| [[w:false (Unix)|false]]
| Shell programming
| Return false value
| 
|-
| [[w:fc (Unix)|fc]]
| Misc
| Process the command history list
| 
|-
| [[w:fg (Unix)|fg]]
| Process Management
| Run jobs in the foreground
| 
|-
| [[w:file (Unix)|file]]
| Filesystem
| Determine file type
| Version 4 AT&T UNIX
|-
| [[w:find|find]]
| Filesystem
| Find files
| Version 1 AT&T UNIX
|-
| [[w:fold (Unix)|fold]]
| Text processing
| Filter for folding lines
| 
|-
| [[w:fort77|fort77]]
| C Programming
| [[w:FORTRAN]] compiler
| 
|-
| [[w:fuser (Unix)|fuser]]
| Process Management
| List [[w:Process_identifier|process IDs]] of all processes that have one or more files open
| 
|-
| [[w:gencat|gencat]]
| Misc
| Generate a formatted message catalog
| 
|-
| [[w:get (Unix)|get]]
| SCCS
| Get a version of an SCCS file
| 
|-
| [[w:getconf|getconf]]
| Misc
| Get configuration values
| 
|-
| [[w:getopts|getopts]]
| Shell Programming
| Parse utility options
| 
|-
| [[w:grep|grep]]
| Misc
| Search text for a pattern
| 
|-
| [[w:hash (Unix)|hash]]
| Misc
| Remember or report utility locations
| 
|-
| [[w:head (Unix)|head]]
| Text processing
| Copy the first part of files
| PWB UNIX
|-
| [[w:iconv|iconv]]
| Text processing
| Codeset conversion
| 
|-
| [[w:id (Unix)|id]]
| Misc
| Return user identity
| 4.4BSD
|-
| [[w:ipcrm|ipcrm]]
| Misc
| Remove a message queue, semaphore set, or shared memory segment identifier
| 
|-
| [[w:ipcs|ipcs]]
| Misc
| Report interprocess communication facilities status
| 
|-
| [[w:jobs (Unix)|jobs]]
| Process Management
| Display status of jobs in the current session
| 
|-
| [[w:join (Unix)|join]]
| Text Processing
| [[w:Relational database|Relational database]] operator
| 
|-
| [[w:kill (Unix)|kill]]
| Process Management
| Terminate or signal processes
| Version 3 AT&T UNIX
|-
| [[w:lex programming tool|lex]]
| C Programming
| Generate programs for [[w:Lexical analyzer|lexical tasks]]
| 
|-
| [[w:link (Unix)|link]]
| Filesystem
| Call link function
| Version 1 AT&T UNIX
|-
| [[w:ln (Unix)|ln]]
| Filesystem
| Link files
| Version 1 AT&T UNIX
|-
| [[w:locale|locale]]
| Misc
| Get locale-specific information
| 
|-
| [[w:localedef|localedef]]
| Misc
| Define locale environment
| 
|-
| [[w:logger (Unix)|logger]]
| Shell programming
| Log messages
| 
|-
| [[w:logname|logname]]
| Misc
| Return the user's login name
| 4.4BSD
|-
| [[w:lp (Unix)|lp]]
| Text Processing
| Send files to a printer
| 
|-
| [[w:ls|ls]]
| Filesystem
| List directory contents
| Version 1 AT&T UNIX
|-
| [[w:M4 (computer language)|m4]]
| Misc
| Macro processor
| PWB UNIX
|-
| [[w:mailx|mailx]]
| Misc
| Process messages
| Version 1 AT&T UNIX
|-
| [[w:make (software)|make]]
| Programming
| Maintain, update, and regenerate groups of programs
| 
|-
| [[w:Manual page (Unix)|man]]
| Misc
| Display system documentation
| 
|-
| [[w:mesg|mesg]]
| Misc
| Permit or deny messages
| Version 1 AT&T UNIX
|-
| [[w:mkdir|mkdir]]
| Filesystem
| Make directories
| Version 1 AT&T UNIX
|-
| [[w:mkfifo|mkfifo]]
| Filesystem
| Make [[w:FIFO|FIFO]] special files
| 4.4BSD
|-
| [[w:more (command)|more]]
| Text processing
| Display files on a page-by-page basis
| 
|-
| [[w:mv|mv]]
| Filesystem
| Move files
| Version 1 AT&T UNIX
|-
| [[w:newgrp|newgrp]]
| Misc
| Change to a new group
| Version 6 AT&T UNIX
|-
| [[w:nice (Unix)|nice]]
| Process Management
| Invoke a utility with an altered nice value
| Version 4 AT&T UNIX
|-
| [[w:nl (Unix)|nl]]
| Text Processing
| Line numbering filter
| 
|-
| [[w:nm (Unix)|nm]]
| C Programming
| Write the name list of an [[w:object file|object file]]
| 
|-
| [[w:nohup|nohup]]
| Process Management
| Invoke a utility immune to [[w:SIGHUP|hangups]]
| 
|-
| [[w:od (Unix)|od]]
| Misc
| Dump files in various formats
| Version 1 AT&T UNIX
|-
| [[w:paste (Unix)|paste]]
| Text processing
| Merge corresponding or subsequent lines of files
| Version 32V AT&T UNIX
|-
| [[w:patch (Unix)|patch]]
| Text processing
| Apply changes to files
| 
|-
| [[w:pathchk|pathchk]]
| Filesystem
| Check pathnames
| 
|-
| [[w:pax (Unix)|pax]]
| Misc
| Portable archive interchange
| 4.4BSD
|-
| [[w:pr (Unix)|pr]]
| Text processing
| Print files
| Version 1 AT&T UNIX
|-
| [[w:printf (Unix)|printf]]
| Shell programming
| Write formatted output
| 4.3BSD-Reno
|-
| [[w:prs|prs]]
| SCCS
| Print an SCCS file
| 
|-
| [[w:ps (Unix)|ps]]
| Process Management
| Report process status
| Version 4 AT&T UNIX
|-
| [[w:pwd|pwd]]
| Filesystem
| print working directory - Return working directory name
| 
|-
| [[w:qalter|qalter]]
| Batch Utilities
| Alter batch job
| 
|-
| [[w:qdel|qdel]]
| Batch Utilities
| Delete batch jobs
| 
|-
| [[w:qhold|qhold]]
| Batch Utilities
| Hold batch jobs
| 
|-
| [[w:qmove|qmove]]
| Batch Utilities
| Move batch jobs
| 
|-
| [[w:qmsg|qmsg]]
| Batch Utilities
| Send message to batch jobs
| 
|-
| [[w:qrerun|qrerun]]
| Batch Utilities
| Rerun batch jobs
| 
|-
| [[w:qrls|qrls]]
| Batch Utilities
| Release batch jobs
| 
|-
| [[w:qselect|qselect]]
| Batch Utilities
| Select batch jobs
| 
|-
| [[w:qsig|qsig]]
| Batch Utilities
| Signal batch jobs
| 
|-
| [[w:qstat (Unix)|qstat]]
| Batch Utilities
| Show status of batch jobs
| 
|-
| [[w:qsub|qsub]]
| Batch Utilities
| Submit a script
| 
|-
| [[w:read (Unix)|read]]
| Shell Programming
| Read a line from standard input
| 
|-
| [[w:readonly|readonly]]
| Misc
| Set the readonly attribute for variables
| 
|-
| [[w:renice|renice]]
| Process Management
| Set [[w:nice values|nice values]] of running processes
| 4.0BSD
|-
| [[w:return (Unix)|return]]
| Shell Programming
| Return from a function
| 
|-
| [[w:rm (Unix)|rm]]
| Filesystem
| Remove directory entries
| Version 1 AT&T UNIX
|-
| [[w:rmdel|rmdel]]
| SCCS
| Remove a delta from an SCCS file
| 
|-
| [[w:rmdir|rmdir]]
| Filesystem
| Remove directories
| Version 1 AT&T UNIX
|-
| [[w:sact (Unix)|sact]]
| SCCS
| Print current SCCS file-editing activity
| 
|-
| [[w:sccs (Unix)|sccs]]
| [[w:Source Code Control_System|SCCS]]
| Front end for the SCCS subsystem
| 
|-
| [[w:sed|sed]]
| Text processing
| Stream editor
| Version 7 AT&T UNIX
|-
| [[w:set (Unix)|set]]
| Misc
| Set or unset options and positional parameters
| 
|-
| [[w:bourne shell|sh]]
| Shell programming
| [[w:shell (computing)|Shell]], the standard command language interpreter
| Version 7 AT&T UNIX
|-
| [[w:shift (Unix)|shift]]
| Shell programming
| Shift positional parameters
| 
|-
| [[w:sleep (Unix)|sleep]]
| Shell programming
| Suspend execution for an interval
| Version 4 AT&T UNIX
|-
| [[w:sort (Unix)|sort]]
| Text Processing
| Sort, merge, or sequence check text files
| 
|-
| [[w:split (Unix)|split]]
| Misc
| Split files into pieces
| Version 3 AT&T UNIX
|-
| [[w:strings (Unix)|strings]]
| C Programming
| Find printable strings in files
| 
|-
| [[w:strip (Unix)|strip]]
| C Programming
| Remove unnecessary information from executable files
| 
|-
| [[w:stty|stty]]
| Misc
| Set the options for a terminal
| 
|-
| [[w:tabs (Unix)|tabs]]
| Misc
| Set terminal tabs
| PWB UNIX
|-
| [[w:tail (Unix)|tail]]
| Text processing
| Copy the last part of a file
| PWB UNIX
|-
| [[w:talk (Unix)|talk]]
| Misc
| Talk to another user
| 4.2BSD
|-
| [[w:tee (command)|tee]]
| Shell programming
| Duplicate [[w:standard input|standard input]]
| 
|-
| [[w:test (Unix)|test]]
| Shell programming
| Evaluate [[w:expression (programming)|expression]]
| 
|-
| [[w:time (Unix)|time]]
| Process Management
| Time a simple command
| Version 3 AT&T UNIX
|-
| [[w:times (Unix)|times]]
| Process Management
| Write process times
| 
|-
| [[w:touch (Unix)|touch]]
| Filesystem
| Change file access and modification times
| Version 7 AT&T UNIX
|-
| [[w:tput|tput]]
| Misc
| Change [[w:terminal|terminal]] characteristics
| System V
|-
| [[w:tr_(Unix)|tr]]
| Text processing
| Translate characters
| Version 4 AT&T UNIX
|-
| [[w:trap (Unix)|trap]]
| Process Management
| Trap signals
| 
|-
| [[w:true (Unix)|true]]
| Shell programming
| Return true value
| 
|-
| [[w:tsort (Unix)|tsort]]
| Text processing
| Topological sort
| Version 7 AT&T UNIX
|-
| [[w:tty (Unix)|tty]]
| Misc
| Return user's [[w:terminal|terminal]] name
| Version 1 AT&T UNIX
|-
| [[w:type (Unix)|type]]
| Misc
| Displays how a name would be interpreted if used as a command
| 
|-
| [[w:ulimit|ulimit]]
| Misc
| Set or report file size limit
| 
|-
| [[w:umask|umask]]
| Misc
| Get or set the file mode creation mask
| 
|-
| [[w:unalias|unalias]]
| Misc
| Remove alias definitions
| 
|-
| [[w:uname|uname]]
| Misc
| Return system name
| PWB UNIX
|-
| [[w:uncompress|uncompress]]
| Misc
| Expand compressed data
| 4.3BSD
|-
| [[w:unexpand|unexpand]]
| Text Processing
| Convert spaces to tabs
| 3.0BSD
|-
| [[w:unget|unget]]
| SCCS
| Undo a previous get of an SCCS file
| 
|-
| [[w:uniq|uniq]]
| Text Processing
| Report or filter out repeated lines in a file
| Version 3 AT&T UNIX
|-
| [[w:unlink (Unix)|unlink]]
| Filesystem
| Call the unlink function
| [[w:Version 1 AT&T UNIX|Version 1 AT&T UNIX]]
|-
| [[w:unset|unset]]
| Misc
| Unset values and attributes of variables and functions
| 
|-
| [[w:uucp|uucp]]
| Network
| System-to-system copy
| 
|-
| [[w:uudecode|uudecode]]
| Network
| Decode a binary file
| 4.0BSD
|-
| [[w:uuencode|uuencode]]
| Network
| Encode a binary file
| 4.0BSD
|-
| [[w:uustat|uustat]]
| Network
| [[w:uucp|uucp]] status inquiry and job control
| 
|-
| [[w:uux (Unix)|uux]]
| Process Management
| Remote command execution
| 
|-
| [[w:val (Unix)|val]]
| SCCS
| Validate SCCS files
| 
|-
| [[w:vi|vi]]
| Text processing
| Screen-oriented (visual) display editor
| BSD
|-
| [[w:wait (command)|wait]]
| Process Management
| Await process completion
| 
|-
| [[w:wc (Unix)|wc]]
| Text processing
| Word, line, and byte or character count
| Version 1 AT&T UNIX
|-
| [[w:what (Unix)|what]]
| SCCS
| Identify SCCS files
| 
|-
| [[w:who (Unix)|who]]
| System Administration
| Display who is on the system
| Version 1 AT&T UNIX
|-
| [[w:write (Unix)|write]]
| Misc
| Write to another user's terminal
| Version 1 AT&T UNIX
|-
| [[w:xargs|xargs]]
| Shell Programming
| Construct argument lists and invoke utility
| PWB UNIX
|-
| [[w:yacc|yacc]]
| C Programming
| Yet another [[w:compiler|compiler]] compiler
| PWB UNIX
|-
| [[w:zcat|zcat]]
| Text Processing
| Expand and concatenate data
| 
|-
|}

=== Unix-like ===
Like [[w:Richard Stallman|RMS]] says, "GNU means GNU's Not Unix". Only [[w:Unix|Unix®]] is really Unix. [[Linux]] and the [[BSD]]s are definitely [[w:Unix-like|Unix-''like'']] though neither one is compliant with the above-mentioned "official" specification. What we present here is based on a set of tools that have been around for a long time. We will be looking at '''generalizations''' that behave in similar ways in ''most'' *nix environments.
==== BusyBox ====
[[w:BusyBox|BusyBox]] is a good example of a more basic collection of utilities and are well suited to the novice. They can be found in [[w:Mini Linux|Mini Linux]] distributions, such as [[Tiny Core Linux]].

'''Exercise 1''' Go to [http://tinycorelinux.com/ TinyCoreLinux.com] and check it out.

==== GNU Core Utilities ====
The [[w:GNU Core Utilities|GNU Core Utilities]] are much more extensive and not for the faint at heart. They are found on most full-sized [[BSD]] and [[Linux]] systems in their full glory.
== Command line arguments ==
This section is under development. 

[[Category:Linux]]
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