---
title: "Per-project terminal colours"
date: 2026-04-23
categories: ["Terminal"]
source: https://andrew-jones.com/blog/per-project-terminal-colours/
---

# Per-project terminal colours

Here's a small but nice improvement I've made to my terminal recently that has been effective for me.

I generally have many terminal windows open across many git-based projects, which I'm regularly switching between.

Now, my terminal windows have different colours for each project.

This is what it looks like:

![Animated Gif showing a dark themed terminal window with the user entering and exiting directories and the colour updating as described in this article.](https://andrew-jones.com/images/blog/2026-04-23/per-project-terminal-colour.gif)



This is the code I've added to my `zshrc`, written with AI assistance:

```bash
# --- Project terminal background ---
# Changes the terminal background colour based on the current git repo.
# Colour is deterministic per repo (derived from the repo root path).
_project_bg() {
  local git_root
  git_root=$(git rev-parse --show-toplevel 2>/dev/null) || {
    printf '\e]111\e\\'
    return
  }
  local hash=$(printf '%s' "$git_root" | md5 -q)
  local r=$(( 16#${hash:0:2} % 71 + 30 ))
  local g=$(( 16#${hash:2:2} % 71 + 30 ))
  local b=$(( 16#${hash:4:2} % 71 + 30 ))
  printf '\e]11;#%02x%02x%02x\e\\' $r $g $b
}
chpwd_functions+=(_project_bg)
_project_bg
```

If the directory is a git repository it gets the path to the repo and creates an MD5 hash of it (using `md5 -q`, which is macOS-specific. Use `md5sum` if on Linux). This ensures the same repository (path) always produces the same colour.

To generate a colour it then extracts 2-character hex pairs from the hash and converts them from hex to decimal. Only values 30-100 are used, so the background is always dark and white text remains readable.

Finally it sets the colour using [OSC 11](https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Operating-System-Commands).

It hooks into Zsh's `chpwd_functions` array, so it automatically runs when the directory changes.

Now when I'm switching between terminal windows I get a clear context signal telling me which project I'm currently in.

I've only tested this with [Ghostty](https://ghostty.org/), and the code can also be found in [my dotfiles repository](https://github.com/andrewrjones/dotfiles).