bash Quick Reference

Invoking the Shell

The command interpreter for the Bash shell (bash) can be invoked as follows:

bash  [options]  [arguments]

Bash can execute commands from a terminal, from a file (when the first argument is a script), or from standard input (if no arguments remain or if -s is specified). The shell automatically prints prompts if standard input is a terminal, or if -i is given on the command line.

On many systems, /bin/sh is a link to Bash. When invoked as sh, Bash acts more like the traditional Bourne shell: login shells read /etc/profile and ~/.profile, and regular shells read $ENV, if it's set. Full details are available in the bash(1) manpage.

Options

-c str

Read commands from string str.

-D, - -dump-strings

Print all $"…" strings in the program.

-i

Create an interactive shell (prompt for input).

-O option

Enable shopt option option.

-p

Start up as a privileged user. Don't read $ENV or $BASH_ENV, don't import functions from the environment, and ignore the value of $SHELLOPTS. The normal fixed-name startup files (such as $HOME/.bash_profile) are read.

-r, - -restricted

Create a restricted shell.

-s

Read commands from standard input. Output from built-in commands goes to file descriptor 1; all other shell output goes to file descriptor 2.

- -debugger

Read the debugging profile at startup, turn on the extdebug option to shopt, and enable function tracing. For use by the Bash debugger (see http://bashdb.sourceforge.net).

- -dump-po-strings

Same as -D, but output in GNU gettext format.

- -help

Print a usage ...