Shell Utilities Glossary
The utilities presented here are the ones standardized by POSIX.1-2017.
Built-in utilities are built into the shell and executed in the same execution environment as the shell.
Utilities that are not built-in are loaded and executed in processes separate from the shell's.
Special built-in
- break
- exit from for, while, or until loop
- continue
- continue for, while, or until loop
- dot
- execute commands in the current environment
- eval
- construct command by concatenating arguments
- exec
- execute commands and open, close, or copy file descriptors
- exit
- cause the shell to exit
- export
- set the export attribute for variables
- readonly
- set the readonly attribute for variables
- return
- return from a function or dot script
- set
- set or unset options and positional parameters
- shift
- shift positional parameters
- times
- write process times
- unset
- unset values and attributes of variables and functions
Other (not special built-in)
Any of the following utilities may be implemented as regular built-in utilities.
- admin
- create and administer SCCS files
- alias
- define or display aliases
- ar
- create and maintain library archives
- asa
- interpret carriage-control characters
- at
- execute commands at a later time
- awk
- pattern scanning and processing language
- basename
- return non-directory portion of a pathname
- batch
- schedule commands to be executed in a batch queue
- bc
- arbitrary-precision arithmetic language
- bg
- run jobs in the background
- c99
- compile standard C programs
- cat
- concatenate and print files
- cd
- change the working directory
- cflow
- generate a C-language flowgraph
- chgrp
- change the file group ownership
- chmod
- change the file modes
- chown
- change the file ownership
- cksum
- write file checksums and sizes
- comm
- select or reject lines common to two files
- crontab
- schedule periodic background work
- csplit
- split files based on context
- cut
- cut out selected fields of each line of a file
- cxref
- generate a C-language program cross-reference table
- date
- write the date and time
- dd
- convert and copy a file
- delta
- make a delta (change) to an SCCS file
- df
- report free disk space
- dirname
- return the directory portion of a pathname
- du
- estimate file space usage
- echo
- write arguments to standard output
- env
- set the environment for command invocation
- expr
- evaluate arguments as an expression
- fc
- process the command history list
- fg
- run jobs in the foreground
- fold
- filter for folding lines
- fuser
- list process IDs of all processes that have one or more files open
- gencat
- generate a formatted message catalog
- get
- get a version of an SCCS file
- grep
- search a file for a pattern
- hash
- remember or report utility locations
- head
- copy the first part of files
- ipcrm
- remove an XSI message queue, semaphore set, or shared memory segment identifier
- ipcs
- report XSI interprocess communication facilities status
- jobs
- display status of jobs in the current session
- join
- relational database operator
- kill
- terminate or signal processes
- lex
- generate programs for lexical tasks
- locale
- get locale-specific information
- logname
- return the user's login name
- lp
- send files to a printer
- ls
- list directory contents
- make
- maintain, update, and regenerate groups of programs
- man
- display system documentation
- mesg
- permit or deny messages
- mkfifo
- make FIFO special files
- more
- display files on a page-by-page basis
- nice
- invoke a utility with an altered nice value
- nm
- write the name list of an object file
- nohup
- invoke a utility immune to hangups
- od
- dump files in various formats
- paste
- merge corresponding or subsequent lines of files
- patch
- apply changes to files
- pax
- portable archive interchange
- pwd
- return working directory name
- qmsg
- send message to batch jobs
- qstat
- show status of batch jobs
- read
- read from standard input into shell variables
- renice
- set nice values of running processes
- rm
- remove directory entries
- rmdel
- remove a delta from an SCCS file
- sact
- print current SCCS file-editing activity
- sccs
- front end for the SCCS subsystem
- sh
- shell, the standard command language interpreter
- sleep
- suspend execution for an interval
- sort
- sort, merge, or sequence check text files
- split
- split a file into pieces
- strings
- find printable strings in files
- strip
- remove unnecessary information from strippable files
- stty
- set the options for a terminal
- tail
- copy the last part of a file
- talk
- talk to another user
- tee
- duplicate standard input
- time
- time a simple command
- touch
- change file access and modification times
- tput
- change terminal characteristics
- tty
- return user's terminal name
- type
- write a description of command type
- ulimit
- set or report file size limit
- umask
- get or set the file mode creation mask
- unget
- undo a previous get of an SCCS file
- uniq
- report or filter out repeated lines in a file
- unlink
- call the unlink function
- uucp
- system-to-system copy
- uustat
- uucp status enquiry and job control
- uux
- remote command execution
- vi
- screen-oriented (visual) display editor
- wait
- await process completion
- wc
- word, line, and byte or character count
- who
- display who is on the system
- write
- write to another user
- xargs
- construct argument lists and invoke utility
- yacc
- yet another compiler compiler
- zcat
- expand and concatenate data