9.2.1 List of standard shell commands

The standard shell commands include special built-in commands and regular built-in commands.

Table 9‒2: List of special built-in commands
Command name	Overview
`.`	Executes a shell script.
`:`	Expands arguments and returns `0` as the return code.
`break`	Exits from a loop.
`continue`	Interrupts loop processing and returns to the beginning of the next cycle of the loop.
`eval`	Concatenates arguments into a command that it executes.
`exec`	Executes a specified command and then exits.
`exit`	Exits the shell.
`export`	Exports shell variables.
`readonly`	Sets the read-only attribute for variables or displays all read-only variables.
`return`	Returns from a function or an external script.
`set`	Sets shell options, creates an array, or displays variable values.
`shift`	Shifts the run-time parameters.
`trap`	Specifies the action when signals and forced termination requests are received.
`typeset`	Declares explicitly the attributes and values of variables and functions.
`unset`	Unsets variable values and attributes.

Table 9‒3: List of regular built-in commands
Command name	Overview
`alias`	Defines aliases.
`builtin`	Executes a built-in command.
`cd`	Changes the current directory.
`command`	Executes a built-in command or external command.
`echo`	Outputs what is specified in arguments to the standard output.
`false`	Returns `1` as the return code.
`getopts`	Parses option arguments.
`kill`	Sends a signal to processes.
`let`	Evaluates the values of arithmetic expressions.
`print`	Outputs what is specified in the arguments to the standard output.
`pwd`	Outputs the path of the current directory.
`read`	Reads from the standard input and stores the input in shell variables.
`test`	Determines the value of a conditional expression.
`times`	Displays the amount of CPU time used by the shell.
`true`	Returns `0` as the return code.
`ulimit` (UNIX only)	Sets or displays information about limits on system resources.
`umask` (UNIX only)	Sets or displays the file mode creation mask.
`unalias`	Removes alias definitions.
`wait`	Waits for child processes to complete.
`whence`	Displays how specified character strings would be interpreted if used as commands.