How to start a shell without any user configuration?

Question

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?

The answers provided below are also useful when, say, one makes a mistake in their `.bashrc` or `.bash_profile` files that causes the shell to exit prematurely. — Gurjeet Singh, Apr 28 '20 at 02:39

score 127 · Answer 1 · edited May 23 '17 at 12:02

127

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.

edited May 23 '17 at 12:02

Community

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answered Jan 27 '14 at 20:30

nnutter

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Thanks for the `env -i` tip! This ended up being a little *too* clean for me, since I just wanted to get rid of my custom settings, but I still needed the system-wide settings. This is what I ended up using: `env -i bash --rcfile /etc/profile` – DaoWen Jul 17 '15 at 18:49
Great tip. The "env -i" is exactly what I needed. My bash_profile was still being read in despite the "--noprofile --norc" . – Marnix A. van Ammers Jan 24 '17 at 19:55
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You didn't need the argument --noprofile as it's only relevant if you have a login shell. – Chad May 21 '17 at 08:07
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It still inherits the `history`. – vulcan raven Sep 23 '19 at 09:52
What's the difference between `env -i bash --norc --noprofile` and `bash --norc --noprofile`? – thc Jun 25 '21 at 07:34
@thc according to man page, `-i, --ignore-environment start with an empty environment` – David Xia Feb 23 '22 at 13:33

score 63 · Accepted Answer · answered Feb 20 '12 at 07:20

63

You can pass the --noprofile and --norc command-line options:

$ bash --noprofile --norc

You will find documentation about these options in the man page.

answered Feb 20 '12 at 07:20

Frédéric Hamidi

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`bash --noprofile --norc` still inherits from parent process. – nnutter Oct 18 '15 at 18:24
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This was good enough for me. Got rid of my aliases, prompts, etc. – wisbucky Sep 15 '17 at 22:33

score 7 · Answer 3 · answered Feb 20 '12 at 07:21

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).

Pierre D · Answer 4 · 2022-02-04T21:45:18.130

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$

How to start a shell without any user configuration?

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