How to customize virtualenv shell prompt

问题

How do you define a custom prompt to use when activating a Python virtual environment?

I have a bash script for activating a virtualenv I use when calling specific Fabric commands. I want the shell prompt to say something like "(fab)" so I can easily distinguish it from other shells I have open. Following this example, I've tried:

#!/bin/bash
script_dir=`dirname $0`
cd $script_dir
/bin/bash -c ". .env/bin/activate; PS1='(fab) '; exec /bin/bash -i"

but there's no change to the prompt. What am I doing wrong?

回答1:

The prompt is set in the virtualenv's activate script (located in the bin folder under the virtualenv). If you only want to change the prompt some times, you could set an environment variable before calling activate (make sure to clear it in the corresponding deactivate file). If you simply want the prompt to be different all the time, you can do that right in activate at the line that looks like

set "PROMPT=(virtualenvname) %PROMPT%"

If you're using virtualenvwrapper, you could do all of this in the postactivate and postdeactivate scripts as well.

回答2:

I couldn't find any way to do this via a script executed as a child process. Calling a separate bash process seems to forget any previously set PS1. However, it turned out to be trivial if I just sourced the script:

#!/bin/bash
script_dir=`dirname $0`
cd $script_dir
. .env/bin/activate
PS1="(fab) "

回答3:

It appears the

exec /bin/bash -i

is resetting the PS1 variable. When I run

export PS1="foo "; bash

it resets it too. Curiously, when I look into the bash sources (shell.c and variables.c) it appears to use

set_if_not ("PS1", primary_prompt);

to init it. But I'm not exactly sure what happens between this and main(). Giving up.

回答4:

I tried on cygwin and on linux (RedHat CentOS) as well. I found solution for both.

CYGWIN

After some investigation I found that the problem is that PS1 is set by /etc/bash.bashrc which overrides the PS1 env.var. So You need to disable to run this file using:

/bin/bash -c ". .env/bin/activate; PS1='(fab) ' exec /bin/bash -i --norc"

/bin/bash -c ". .env/bin/activate; export PS1='(fab) '; exec /bin/bash -i --norc"

LINUX

It works much simpler:

/bin/bash -c ". .env/bin/activate; PS1='(fab) ' exec /bin/bash -i"

/bin/bash -c ". .env/bin/activate; export PS1='(fab) '; exec /bin/bash -i"

If the script You are calling does not export the variables (and I suppose it does not) and the set variables does not appears in the environment then You could try something like this:

/bin/bash -c "PS1='(fab) ' exec /bin/bash --rcfile .env/bin/activate; "

I hope I could help!

来源：https://stackoverflow.com/questions/20524692/how-to-customize-virtualenv-shell-prompt

标签

python

bash

virtualenv