|GNU Bash Reference Manual|
by Chet Ramey and Brian Fox
Paperback (6"x9"), 180 pages
RRP £19.95 ($29.95)
"An essential resource .... the most detailed coverage available for all aspects of Bash" --- Linux User and Developer Magazine (Issue 37, Mar 2004) Get a printed copy>>>
6.2 Bash Startup Files
This section describes how Bash executes its startup files. If any of the files exist but cannot be read, Bash reports an error. Tildes are expanded in file names as described above under Tilde Expansion (see section 3.5.2 Tilde Expansion).
Interactive shells are described in section 6.3 Interactive Shells.
184.108.40.206 Invoked as an interactive login shell, or with
When Bash is invoked as an interactive login shell, or as a
non-interactive shell with the
--login option, it first reads and
executes commands from the file ‘/etc/profile’, if that file exists.
After reading that file, it looks for ‘~/.bash_profile’,
‘~/.bash_login’, and ‘~/.profile’, in that order, and reads
and executes commands from the first one that exists and is readable.
--noprofile option may be used when the shell is started to
inhibit this behavior.
When a login shell exits, Bash reads and executes commands from the file ‘~/.bash_logout’, if it exists.
220.127.116.11 Invoked as an interactive non-login shell
When an interactive shell that is not a login shell is started, Bash
reads and executes commands from ‘~/.bashrc’, if that file exists.
This may be inhibited by using the
--rcfile file option will force Bash to read and
execute commands from file instead of ‘~/.bashrc’.
So, typically, your ‘~/.bash_profile’ contains the line
if [ -f ~/.bashrc ]; then . ~/.bashrc; fi
after (or before) any login-specific initializations.
18.104.22.168 Invoked non-interactively
When Bash is started non-interactively, to run a shell script,
for example, it looks for the variable
BASH_ENV in the environment,
expands its value if it appears there, and uses the expanded value as
the name of a file to read and execute. Bash behaves as if the
following command were executed:
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
but the value of the
PATH variable is not used to search for the
As noted above, if a non-interactive shell is invoked with the
--login option, Bash attempts to read and execute commands from the
login shell startup files.
22.214.171.124 Invoked with name
If Bash is invoked with the name
sh, it tries to mimic the
startup behavior of historical versions of
sh as closely as
possible, while conforming to the POSIX standard as well.
When invoked as an interactive login shell, or as a non-interactive
shell with the
--login option, it first attempts to read
and execute commands from ‘/etc/profile’ and ‘~/.profile’, in
--noprofile option may be used to inhibit this behavior.
When invoked as an interactive shell with the name
looks for the variable
ENV, expands its value if it is defined,
and uses the expanded value as the name of a file to read and execute.
Since a shell invoked as
sh does not attempt to read and execute
commands from any other startup files, the
--rcfile option has
A non-interactive shell invoked with the name
sh does not attempt
to read any other startup files.
When invoked as
sh, Bash enters POSIX mode after
the startup files are read.
126.96.36.199 Invoked in POSIX mode
When Bash is started in POSIX mode, as with the
--posix command line option, it follows the POSIX standard
for startup files.
In this mode, interactive shells expand the
and commands are read and executed from the file whose name is the
No other startup files are read.
188.8.131.52 Invoked by remote shell daemon
Bash attempts to determine when it is being run by the remote shell
rshd. If Bash determines it is being run by
rshd, it reads and executes commands from ‘~/.bashrc’, if that
file exists and is readable.
It will not do this if invoked as
--norc option may be used to inhibit this behavior, and the
--rcfile option may be used to force another file to be read, but
rshd does not generally invoke the shell with those options or
allow them to be specified.
184.108.40.206 Invoked with unequal effective and real UID/GIDs
If Bash is started with the effective user (group) id not equal to the
real user (group) id, and the
-p option is not supplied, no startup
files are read, shell functions are not inherited from the environment,
SHELLOPTS variable, if it appears in the environment, is ignored,
and the effective user id is set to the real user id.
-p option is supplied at invocation, the startup behavior is
the same, but the effective user id is not reset.
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