Invocation

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.