The GNU Bash Reference Manual

Author(s)

The Free Software Foundation

Subject

This text is a brief description of the features that are present in the Bash shell.

Index

1. Introduction
   • What is Bash?
   • What is a shell?
2. Definitions
3. Basic Shell Features
   • Shell Syntax
     • Shell Operation
     • Quoting
       • Escape Character
       • Single Quotes
       • Double Quotes
       • ANSI-C Quoting
       • Locale-Specific Translation
     • Comments
   • Shell Commands
     • Simple Commands
     • Pipelines
     • Lists of Commands
     • Looping Constructs
       • until
       • while
       • for
     • Conditional Constructs
       • if
       • case
       • select
       • ((...))
       • [[...]]
     • Grouping Commands
       • ()
       • {}
   • Shell Functions
   • Shell Parameters
     • Positional Parameters
     • Special Parameters
       • *
       • @
       • #
       • ?
       • -
       • $
       • !
       • 0
       • _
   • Shell Expansions
     • Brace Expansion
     • Tilde Expansion
     • Shell Parameter Expansion
     • Command Substitution
     • Arithmetic Expansion
     • Process Substitution
     • Word Splitting
     • Filename Expansion
       • Pattern Matching
     • Quote Removal
   • Redirections
     • Redirecting Input
     • Redirecting Output
     • Appending Redirected Output
     • Redirecting Standard Output and Standard Error
     • Here Documents
     • Duplicating File Descriptors
     • Opening File Descriptors for Reading and Writing
   • Executing Commands
     • Simple Command Expansion
     • Command Search and Execution
     • Command Execution Environment
     • Environment
     • Exit Status
     • Signals
   • Shell Scripts
4. Shell Builtin Commands
   • Bourne Shell Builtins
     • :(colon)
     • .(period)
     • break
     • cd
     • continue
     • eval
     • exec
     • exit
     • export
     • getopts
     • hash
     • pwd
     • readonly
     • return
     • shift
     • test (or [])
     • times
     • trap
     • umask
     • unset
   • Bash Builtin Commands
     • alias
     • bind
     • builtin
     • command
     • declare
     • echo
     • enable
     • help
     • let
     • local
     • logout
     • printf
     • read
     • shopt
     • source
     • type
     • typeset
     • ulimit
     • unalias
   • The Set Builtin
     • -a
     • -b
     • -e
     • -f
     • -h
     • -k
     • -m
     • -n
     • -o option-name
     • -p
     • -t
     • -u
     • -v
     • -x
     • -B
     • -C
     • -H
     • -P
     • --
     • -
   • Special Builtins
5. Shell Variables
   • Bourne Shell Variables
     • CDPATH
     • HOME
     • IFS
     • MAIL
     • MAILPATH
     • OPTARG
     • OPTIND
     • PATH
     • PS1
     • PS2
   • Bash Variables
     • BASH
     • BASH_ENV
     • BASH_VERSION
     • BASH_VERSINFO
     • COLUMNS
     • COMP_CWORD
     • COMP_LINE
     • COMP_POINT
     • COMP_WORDS
     • COMPREPLY
     • DIRSTACK
     • EUID
     • FCEDIT
     • FIGNORE
     • FUNCNAME
     • GLOBIGNORE
     • GROUPS
     • histchars
     • HISTCMD
     • HISTCONTROL
     • HISTFILE
     • HISTFILESIZE
     • HISTIGNORE
     • HISTSIZE
     • HOSTFILE
     • HOSTNAME
     • HOSTTYPE
     • IGNOREEOF
     • INPUTRC
     • LANG
     • LC_ALL
     • LC_COLLATE
     • LC_CTYPE
     • LC_MESSAGES
     • LC_NUMERIC
     • LINENO
     • LINES
     • MACHTYPE
     • MAILCHECK
     • OLDPWD
     • OPTERR
     • OSTYPE
     • PIPESTATUS
     • POSIXLY_CORRECT
     • PPID
     • PROMPT_COMMAND
     • PS3
     • PS4
     • PWD
     • RANDOM
     • REPLY
     • SECONDS
     • SHELLOPTS
     • SHLVL
     • TIMEFORMAT
     • TMOUT
     • UID
6. Bash Features
   • Invoking Bash
     • --dump-po-strings
     • --dump-strings
     • --help
     • --init-file name, --rcfile filename
     • --login
     • --noediting
     • --noprofile
     • --norc
     • --posix
     • --restricted
     • --verbose
     • --version
     • -c string
     • -i
     • -r
     • -s
     • -D
     • [-+]O [shopt_option]
     • --
   • Bash Startup Files
     • Invoked as an interactive login shell, or with --login
     • Invoked as an interactive non-login shell
     • Invoked non-interactively
     • Invoked with name sh
     • Invoked in posix mode
     • Invoked by remote shell daemon
     • Invoked with unequal effective and real uid/gids
   • Interactive Shells
     • What is an Interactive Shell?
     • Is this Shell Interactive?
     • Interactive Shell Behavior
   • Bash Conditional Expressions
   • Shell Arithmetic
   • Aliases
   • Arrays
   • The Directory Stack
     • Directory Stack Builtins
       • dirs
       • popd
       • pushd
   • Controlling the Prompt
   • The Restricted Shell
   • Bash POSIX Mode
7. Job Control
   • Job Control Basics
   • Job Control Builtins
     • bg
     • fg
     • jobs
     • kill
     • wait
     • disown
     • suspend
   • Job Control Variables
     • auto_resume