git-prompt.sh re-implemented with gawk, and required git version >= 2.11.0

git-bash.awk

#!/usr/bin/env bash

git rev-parse 2>/dev/null && \
  ( [[ "$(git rev-parse --is-bare-repository)" == true ]] && (echo '&' ; echo "# branch.head $(git rev-parse --abbrev-ref HEAD)") || \
    [[ "$(git rev-parse --is-inside-git-dir)"  == true ]] && echo '@' || \
    (git rev-parse --verify -q refs/stash >/dev/null && echo '$' ; git status --porcelain=v2 -b --ignored) \
  ) | gawk '

/^&$/              { bare++;      next; }
/^@$/              { insidegit++; next; }
/^\$$/             { stashed++;   next; }
/^# branch\.head / { head = $0; sub(/# branch\.head /, "", head); next; }
/^# branch\.ab /   { match($0, /^# branch\.ab \+([0-9]+) -([0-9]+)$/, ab); ahead = ab[1]; behind = ab[2]; next; }
/^! /              { ignored++;   next; }
/^\? /             { untracked++; next; }
/^[12] U. /        { conflicts++; next; }
/^[12] .U /        { conflicts++; next; }
/^[12] DD /        { conflicts++; next; }
/^[12] AA /        { conflicts++; next; }
/^[12] .M /        { changed++;         }
/^[12] .D /        { changed++;         }
/^[12] [^.]. /     { staged++;          }

END {
  printf(" (");

  if (bare != 0) {
    printf("\033[1;32m%s\033[0m:\033[0;32m%s\033[0m", "BARE", head);
  } else if (insidegit != 0) {
    printf("\033[1;32m%s\033[0m", "GIT_DIR");
  } else {
    printf("\033[0;32m%s\033[0m", head);
    if (stashed + ignored + untracked + conflicts + changed + staged != 0) {
      printf(" ");
      if (stashed  ) printf("\033[1;34m$\033[0m"                );
      if (staged   ) printf("\033[0;32m+%d\033[0m",    staged   );
      if (changed  ) printf("\033[0;31m*%d\033[0m",    changed  );
      if (untracked) printf("\033[0;35m%%%d\033[0m",   untracked);
      if (ignored  ) printf("\033[1;30mi%d\033[0m",    ignored  );
      if (conflicts) printf("\033[1;41;30m!%d\033[0m", conflicts);
    }
    if (behind + ahead != 0) {
      if (behind   ) printf("\033[1;40;31m↓%d\033[0m", behind   );
      if (ahead    ) printf("\033[1;40;36m↑%d\033[0m", ahead    );
    } else {
      printf("\033[0m=");
    }
  }

  printf("\033[0m)");
}'

# vim: set ft=awk:

It's based on josuahdemangeon's git-prompt posted on Reddit, and try to add features and tweak styles/colors to overtake the official git-prompt.sh, and make slight improvement (reduce the number of the git command calls) by using new Porcelain Format Version 2 of "git status" command introduced from Git v2.11.0.

Thank you for improving this script!

I saw you were using a shebang to bash, but you can make it compatible with any shell with very few changes https://gist.github.com/josuah/2fe1e6f145b59d4d1155dc2ab84d1cf8/revisions

Also, it seems to work with any awk, even busybox's awk, so you may not require gawk.
I tried to make light changes keeping the same coding style and indentation.

Finally, I'm using the next keyword rather than a m = 0 and m = 1 && ....

Pull some changes if you want, do not if you don't, feel free.

Thank you @josuah for your improvement, I had merged some parts of your contributions back.
I'm really glad you like it and contribute my changes back to your version.

But, now, I will stick with bash and gawk, the reason I had commented in your gist.