Bash Builtin Commands
The set of portable commands.
Commands
Command |
Description |
Example |
. |
Alias for source |
|
: |
No-op |
|
alias |
Creates an alias |
|
bind |
|
|
builtin |
Executes a builtin command |
|
caller |
|
|
cd |
Changes the current working directory |
|
command |
Executes a command |
|
declare |
Set a variable, optionally with a value |
|
dirs |
|
|
disown |
|
|
echo |
|
|
enable |
|
|
eval |
Executes a command |
|
exec |
Replaces the shell with a command |
|
exit |
Causes a script or shell to exit immediately |
|
export |
Marks one or more names as variables to be included in the environment of subsequently-called commands |
export varname="some value" |
fc |
|
|
getopts |
|
|
hash |
|
|
help |
Prints helpful information about a builtin command |
|
history |
|
|
kill |
|
|
let |
|
|
local |
Only valid within a function definition; see here |
|
logout |
Exits a login shell immediately |
|
mapfile |
|
|
popd |
|
|
printf |
|
|
pushd |
|
|
pwd |
Prints the current working directory |
|
read |
|
|
readarray |
|
|
readonly |
|
|
set |
Sets a shell option |
|
shift |
Renames the positional variables |
|
shopt |
Sets a shell option |
|
source |
|
|
test |
Executes a test |
|
time |
|
|
trap |
Creates a trap |
|
typeset |
|
|
unalias |
Removes an alias |
|
unset |
Unsets a shell option |
|
wait |
|
|
Builtin
builtin can be useful to call a builtin command when there is a custom command with the same name.
Cd
Calling cd without an argument is the same as cd ~.
cd - changes the current working directory to the previous working directory.
Command
command can be useful to call a command when there is a function with the same name.
command is also commonly used to determine if a command is locally available.
if ! command -v mypy >/dev/null 2>&1; then echo "cannot locate mypy; is it installed?" exit fi
Declare
When used within a function definition, the variable is set to local scope.
To create a variable that is marked for export, use:
declare -x myvar
To create a variable that is marked for tracing, use:
declare -t myvar
To create a read-only constant, use:
declare -r myconst
To create an integer variable, use:
declare -i myinteger
To create an array, use:
declare -a myarray
To create an associative array, use:
declare -A myarray
With some exceptions, these options can be combined. Additionally, options can be explicitly disabled by substituting the dash (-) with a plus sign (+).
Reserved Keywords
Some parts of the language are technically implemented as a command.
See here for break and continue.
See here for return.
See here for compgen, complete, and compopt`.
See here for bg, coproc, fg, and jobs.