How to start a shell without any user configuration?
LinuxMacosBashShellLinux Problem Overview
I need to use a "clean" shell (e.g. bash) under Linux/OSX terminal without any user configuration, but it reads config info from some files (e.g ~/.bashrc) every time it starts. I can modify the file every time I need a "clean" shell, and revert it back when I finished, but is there any easier ways to do this, for example a command?
Linux Solutions
Solution 1 - Linux
Running bash --noprofile --norc
still inherited from parent process. Based on a similar question I found that the way I interpreted this question env -i bash --norc --noprofile
was what I would want.
Solution 2 - Linux
You can pass the --noprofile
and --norc
command-line options:
$ bash --noprofile --norc
You will find documentation about these options in the man page.
Solution 3 - Linux
Use --noprofile --norc:
--noprofile
Do not read either the system-wide startup file /etc/profile or any of the personal initializa‐
tion files ~/.bash_profile, ~/.bash_login, or ~/.profile. By default, bash reads these files
when it is invoked as a login shell (see INVOCATION below).
--norc Do not read and execute the system wide initialization file /etc/bash.bashrc and the personal
initialization file ~/.bashrc if the shell is interactive. This option is on by default if the
shell is invoked as sh.
(from the manpage).
Solution 4 - Linux
It is often desirable to launch an entirely blank bash:
- no environment variables carried from the parent shell;
- an empty home dir without any package-specific configuration files (e.g.
.gitconfig
and.local/...
); - no shell configuration files.
This works for me both on MacOS and Linux:
env -i HOME=$(mktemp -d) bash --noprofile --norc
cd
In that bash shell, the HOME
dir is that test dir just created (change the name if needed), and there are no particular settings. The only environment variables that are set are PWD
, HOME
, and SHLVL
.
Upon starting bash, the PWD
is where we were before, so we need to do that initial cd
.
Example (Linux):
$ env -i HOME=$(mktemp -d) bash --noprofile --norc
bash-5.0$ cd
bash-5.0$ pwd
/tmp/tmp.mwgHRQE1aJ
bash-5.0$ printenv
PWD=/tmp/tmp.mwgHRQE1aJ
HOME=/tmp/tmp.mwgHRQE1aJ
SHLVL=1
OLDPWD=/home/xxxxxxxxxxxxxxxxx
_=/usr/bin/printenv
bash-5.0$