Make shell prompt show current head when in a VCS

Question

When using a VCS, (I use Mercurial and Git in Linux, Bash prompt), is there any way to have the prompt show the current head or tag in the directory?

More than once I have shot myself in the foot by working in one head when thinking I was in another, for example, pushing v0.3 to testing when they needed v.02, or patching bugs in dev then they needed to be patched in prod, or vice versa.

Answer 1

For Mercurial, there is hg-prompt by Steve Losh. This is an extension for Mercurial that gives you a new hg prompt command. You put a call to this command into your PS1 environment variable:

export PS1='\u in \w`hg prompt "{on {branch}}{status}{update}" 2>/dev/null` $'

to get a prompt like

user in ~/src/project on feature-branch? $

where the ? at the end tells you that there is an unknown file in your repository.

Steve wrote a blog post about his Zsh prompt and there are more colorful prompts from the documentation:

Answer 2

Git provides a bash function that shows the current branch or hash if headless. Look for __git_ps1 in the bash_completion file.

My ~/.bashrc contains these lines:

Green='\[\e[0;32m\]'
BIGreen='\[\e[1;92m\]'
Color_Off='\[\e[0m\]'
export PS1=$Green'\w $(__git_ps1 "(%s)")'$BIGreen'$ '$Color_Off

which will create a prompt like this:

~/repos/myproject (master)$