`ps1-git-efficient`

Minimalistic shell-prompt `git status` fragment generator

What it looks like

From within a git repo, the prompt might look like this:

hostname dir (<>?*branch)$

where the git part this script generates has the following components:

branch: current branch (or HEAD if detached)
< and >: the local branch is ahead and/or behind upstream
?: there are untracked file
*: there are modified tracked files (including conflicts, file-type changes, deleted / added / unmerged files)

Usage

Bourne shells (POSIX `sh`, `bash` etc)

PS1='\h \W$(/path/to/ps1-git-efficient.sh --ps1_print)\$ '

## or load script & function beforehand, combine with other generators
tmploader() { . /path/to/ps1-git-efficient.sh; }; tmploader
PS1='\h \W$(gen1; ps1git_efficient; gen2)\$ '

Large repos

For large git repositories, even a single git status can be slow (it has to examine recursively the entire repo). Set ps1git_efficient_status=false in your shell: status will be replaced with a simpler git command that only detects and prints the current branch.

Tweaks

The script / function also accept an additional optional format argument (for the script: after --ps1_print). The default format is ' (%s)'. You can customize it, for example to add colors:

# precompute global format variable, use it in PS1 call
ps1git_efficient_fmt=" ($(tput setaf 1)%s$(tput sgr0))"
PS1='\h \W $(ps1git_efficient "$ps1git_efficient_fmt")\$ '

Fish

TODO: create .fish function and use string. In the meantime, you could

# add `ps1-git-efficient.sh --ps1_print` to `fish(_right)_prompt`
# e.g. in Disco prompt: replace other git calls with
set -l vcs = (/path/to/ps1-git-efficient.sh --ps1_print)

Performance

there is a single call to git status
it uses --no-optional-locks to avoid git's habit of opportunistically updating .git/index (creating & removing a lock file in the process, even when there are no changes) which should probably not happen every time you press <Enter> in the shell
string processing uses POSIX shell built-in parameter expansion, without any overhead from external utilities (sed, grep, head etc)
if you source the script from .bashrc or similar, PS1 can contain a single function call to a single combined generator which calls the ps1git_efficient function

Here's an example that optionally prints the exit code from the previous command (if non-zero and not ^C) and also git info (if within a repo):

# source the script with POSIX-compliant `.`
# wrap `.` in function to avoid "$@" (argv) leakage
tmploader() { . /path/to/ps1-git-efficient.sh; }; tmploader

ps1gen() {
  # process $? status before calling any other commands
  local s=${?#0*}; s=${s#130}; s=${s:+' ?'$s}
  ps1git_efficient
  printf %s "$s"
}
PS1='\h \W$(ps1gen)\$ '  # single subshell for ps1gen()

Copyright

Alin Mr almr.oss@outlook.com / MIT license.

kstr0k/ps1-git-efficient

ps1-git-efficient

Minimalistic shell-prompt git status fragment generator