B.1 Invocation
Table 2.1 and Table 2.2 list the options you can use when invoking bash 2.x and 1.x, respectively. [B]The multicharacter options must appear on the command line before the single-character options. In addition to these, any set option can be used on the command line; see Table 2.6. Login shells are usually invoked with the options -i (interactive), -s (read from standard input), and -m (enable job control).
[B] At the time of writing, the old 1.x versions of bash are still widely used. We strongly recommend that you upgrade to the latest version. We have included a table of old options (Table 2.2) just in case you encounter an old version of the shell.
Table B.1. Command-Line Options |
| Option | Meaning |
| -c string | Commands are read from string, if present. Any arguments after string are interpreted as positional parameters, starting with $0. |
| -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. This also turns on the -n option. |
| -i | Interactive shell. Ignore signals TERM, INT, and QUIT. With job control in effect, TTIN, TTOU, and TSTP are also ignored. |
| -o option | Takes the same arguments as set -o. |
| -s | Read commands from the standard input. If an argument is given to bash, this flag takes precedence (i.e., the argument won't be treated as a script name and standard input will be read). |
| -r | Restricted shell. See Chapter 10. |
| - | Signals the end of options and disables further option processing. Any options after this are treated as filenames and arguments. -- is synonymous with -. |
| --dump-strings | Does the same as -D. |
| --help | Displays a usage message and exits. |
| --login | Makes bash act as if invoked as a login shell. |
| --noediting | Does not use the GNU readline library to read command lines if interactive. |
| --noprofile | Does not read the startup file /etc/profile or any of the personal initialization files. |
| --norc | Does not read the initialization file ~/.bashrc if the shell is interactive. This is on by default if the shell is invoked as sh. |
| --posix | Changes the behavior of bash to follow the POSIX guidelines more closely where the default operation of bash is different. |
| --quiet | Shows no information on shell startup. This is the default. |
| --rcfile file | Executes commands read from file instead of the initialization file ~/.bashrc, if the shell is interactive. |
| --version | Shows the version number of this instance of bash and then exits. |
Table B.2. Old Command-Line Options |
| Option | Meaning |
| -c string | Commands are read from string, if present. Any arguments after string are interpreted as positional parameters, starting with $0. |
| -i | Interactive shell. Ignore signals TERM, INT, and QUIT. With job control in effect, TTIN, TTOU, and TSTP are also ignored. |
| -s | Read commands from the standard input. If an argument is given to bash, this flag takes precedence (i.e., the argument won't be treated as a script name and standard input will be read). |
| -r | Restricted shell. See Chapter 10. |
| - | Signals the end of options and disables further option processing. Any options after this are treated as filenames and arguments. -- is synonymous with -. |
| -norc | Does not read the initialization file ~/.bashrc if the shell is interactive. This is on by default if the shell is invoked as sh. |
| -noprofile | Does not read the startup file /etc/profile or any of the personal initialization files. |
| -rcfile file | Executes commands read from file instead of the initialization file ~/.bashrc, if the shell is interactive. |
| -version | Shows the version number of this instance of bash when starting. |
| -quiet | Shows no information on shell startup. This is the default. |
| -login | Makes bash act as if invoked as a login shell. |
| -nobraceexpansion | Does not perform curly brace expansion. |
| -nolineediting | Does not use the GNU readline library to read command lines if interactive. |
| -posix | Changes the behavior of bash to follow the POSIX guidelines more closely where the default operation of bash is different. |