Invoking Bash

Bash Reference Manual. Node: Invoking Bash

5.1: Invoking Bash

bash [long-opt] [-ir] [-abefhkmnptuvxdBCDHP] [-o option] [argument ...]
bash [long-opt] [-abefhkmnptuvxdBCDHP] [-o option] -c string [argument ...]
bash [long-opt] -s [-abefhkmnptuvxdBCDHP] [-o option] [argument ...]

In addition to the single-character shell command-line options (see The Set Builtin), there are several multi-character options that you can use. These options must appear on the command line before the single-character options in order for them to be recognized.

`--dump-po-strings`	Equivalent to ``-D`', but the output is in the GNU `gettext` PO (portable object) file format.
`--dump-strings`	Equivalent to ``-D`'.
`--help`	Display a usage message on standard output and exit sucessfully.
`--login`	Make this shell act as if it were directly invoked by login. This is equivalent to ``exec -l bash`' but can be issued from another shell, such as `csh`. ``exec bash --login`' will replace the current shell with a Bash login shell.
`--noediting`	Do not use the GNU Readline library (see Command Line Editing) to read interactive command lines.
`--noprofile`	Don't load the system-wide startup file ``/etc/profile`' or any of the personal initialization files ``~/.bash_profile`', ``~/.bash_login`', or ``~/.profile`' when Bash is invoked as a login shell.
`--norc`	Don't read the ``~/.bashrc`' initialization file in an interactive shell. This is on by default if the shell is invoked as `sh`.
`--posix`	Change the behavior of Bash where the default operation differs from the POSIX 1003.2 standard to match the standard. This is intended to make Bash behave as a strict superset of that standard. See Bash POSIX Mode, for a description of the Bash POSIX mode.
`--rcfile filename`	Execute commands from `filename` (instead of ``~/.bashrc`') in an interactive shell.
`--restricted`	Make the shell a restricted shell (see The Restricted Shell).
`--verbose`	Equivalent to ``-v`'.
`--version`	Show version information for this instance of Bash on the standard output and exit successfully.

There are several single-character options that may be supplied at invocation which are not available with the set builtin.

`-c string`	Read and execute commands from `string` after processing the options, then exit. Any remaining arguments are assigned to the positional parameters, starting with `$0`.
`-i`	Force the shell to run interactively.
`-r`	Make the shell a restricted shell (see The Restricted Shell).
`-s`	If this option is present, or if no arguments remain after option processing, then commands are read from the standard input. This option allows the positional parameters to be set when invoking an interactive shell.
`-D`	A list of all double-quoted strings preceded by ``$`' is printed on the standard ouput. These are the strings that are subject to language translation when the current locale is not `C` or `POSIX` (see Locale Translation). This implies the ``-n`' option; no commands will be executed.
`--`	A `--` signals the end of options and disables further option processing. Any arguments after the `--` are treated as filenames and arguments.

An interactive shell is one whose input and output are both connected to terminals (as determined by isatty(3)), or one started with the `-i' option.

If arguments remain after option processing, and neither the `-c' nor the `-s' option has been supplied, the first argument is assumed to be the name of a file containing shell commands (see Shell Scripts). When Bash is invoked in this fashion, $0 is set to the name of the file, and the positional parameters are set to the remaining arguments. Bash reads and executes commands from this file, then exits. Bash's exit status is the exit status of the last command executed in the script. If no commands are executed, the exit status is 0.

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