Initial commit.

README.md

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+# Python venv in prompt
+
+A bash-only, small tool to show Python venvs info in bash's prompt.
+
+Here's what it looks like (I also use
+[git-prompt](https://raw.githubusercontent.com/git/git/master/contrib/completion/git-prompt.sh).
+
+![](example.png)
+
+
+## Installation
+
+Clone the repo and source `python-prompt.sh` from your `~/.bashrc`, I
+like doing so by having a list of `extra` things to load, like this:
+
+```bash
+for extra in /etc/bash_completion ~/.git-prompt.sh ~/clones/python-prompt/python-prompt.sh
+do
+    if [ -f "$extra" ]
+    then
+        . $extra
+    fi
+done
+```
+
+## Setup
+
+Don't forget the installation step!
+
+<details>
+<summary>TL;DR:</summary>
+
+```bash
+if ! [[ -f ~/.fonts/dejavu/DejaVuSansMonoNerdFontCompleteMono.ttf ]]
+then
+    mkdir -p ~/.fonts/dejavu/
+    wget -qO ~/.fonts/dejavu/DejaVuSansMonoNerdFontCompleteMono.ttf https://github.com/ryanoasis/nerd-fonts/raw/master/patched-fonts/DejaVuSansMono/Regular/complete/DejaVu%20Sans%20Mono%20Nerd%20Font%20Complete%20Mono.ttf
+fi
+
+PY_BLUE_FG='\e[38;2;53;112;160m'
+PY_BLUE_BG='\e[48;2;53;112;160m'
+PY_YELLOW_FG='\e[38;2;255;222;87m'
+PY_YELLOW_BG='\e[48;2;255;222;87m'
+
+PY_PROMPT='$(python_prompt "${PY_BLUE_FG}🭮${PY_BLUE_BG}${PY_YELLOW_FG}  %s \e[0m${PY_BLUE_FG}🭬\e[0m")'
+
+PS1="\u@\H:\w${PY_PROMPT}\n\$ "
+```
+
+</details>
+
+In your `~/.bashrc`, let's imagine you're having a `PS1` like this:
+
+```bash
+PS1="\u@\H\$ "
+```
+
+You can inject `python-prompt` in it like this:
+
+```bash
+PY_PROMPT='$(python_prompt "(%s)")'
+PS1="\u@\H${PY_PROMPT}\$ "
+```
+
+But it's a bit ugly, we can do better by adding Python colors:
+
+```bash
+PY_BLUE_FG='\e[38;2;53;112;160m'
+PY_BLUE_BG='\e[48;2;53;112;160m'
+PY_YELLOW_FG='\e[38;2;255;222;87m'
+PY_YELLOW_BG='\e[48;2;255;222;87m'
+PY_PROMPT='$(python_prompt "${PY_BLUE_FG}${PY_BLUE_BG}${PY_YELLOW_FG} %s \e[0m${PY_BLUE_FG}\e[0m")'
+```
+
+It's not perfect but it starts to work for me. If you feel like
+installing a few more fonts you can try `apt install fonts-noto-core`
+(or any font having `U+1FB6E RIGHT TRIANGULAR ONE QUARTER BLOCK` and
+`U+1FB6C LEFT TRIANGULAR ONE QUARTER BLOCK`) and play with those
+characters like:
+
+```bash
+PY_PROMPT='$(python_prompt "${PY_BLUE_FG}🭮${PY_BLUE_BG}${PY_YELLOW_FG} %s \e[0m${PY_BLUE_FG}🭬\e[0m")'
+```
+
+For the last touch, I like to add a little Python logo in there, my `~/.bashrc` contains:
+
+```bash
+if ! [[ -f ~/.fonts/dejavu/DejaVuSansMonoNerdFontCompleteMono.ttf ]]
+then
+    mkdir -p ~/.fonts/dejavu/
+    wget -qO ~/.fonts/dejavu/DejaVuSansMonoNerdFontCompleteMono.ttf https://github.com/ryanoasis/nerd-fonts/raw/master/patched-fonts/DejaVuSansMono/Regular/complete/DejaVu%20Sans%20Mono%20Nerd%20Font%20Complete%20Mono.ttf
+fi
+```
+
+so I can use a Python logo from this font like this:
+
+```bash
+PY_PROMPT='$(python_prompt "${PY_BLUE_FG}🭮${PY_BLUE_BG}${PY_YELLOW_FG}  %s \e[0m${PY_BLUE_FG}🭬\e[0m")'
+```
+
+My real prompt is a tad more complicated than that, with hostname color
+varying on the actual hostname, git prompt, exit status, ... free to
+get inspiration from it:
+https://git.afpy.org/mdk/dotfiles/src/branch/main/.bashrc
+
+
+## But `activate` already shows the info...
+
+Oh yes, but I do not use `source .venv/bin/activate`, I'm using
+[direnv](https://direnv.net/) to automatically
+create/activate/deactivate my venvs, using a simple bash function like this:
+
+```bash
+venv()
+{
+    printf "VIRTUAL_ENV=.venv\nlayout python3\n" > .envrc
+    direnv allow .
+}
+```
+
+so when I need a venv I just type `venv` and boom it's all set:
+
+![](venv.png)
+
+
+## Alternatives
+
+I've heard of:
+
+- [Liquid Prompt](https://github.com/liquidprompt/liquidprompt)
+- [PowerLevel10k](https://github.com/romkatv/powerlevel10k)
+- [Starship](https://github.com/starship/starship)
+- [Powerline](https://github.com/powerline/powerline)
+- [Pure](https://github.com/sindresorhus/pure)
+- [Oh-My-Phosh](https://ohmyposh.dev/)
+
+But I did not tested any of them.

python-prompt.sh

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+trim() {
+    local var="$*"
+    # remove leading whitespace characters
+    var="${var#"${var%%[![:space:]]*}"}"
+    # remove trailing whitespace characters
+    var="${var%"${var##*[![:space:]]}"}"
+    printf '%s' "$var"
+}
+
+shortest()
+{
+    # Returns the shortest of two strings
+    if [[ ${#1} -lt ${#2} ]]
+    then
+        printf "%s" "$1"
+    else
+        printf "%s" "$2"
+    fi
+}
+
+python_ps1()
+{
+    local relative venvpath pyversion _
+
+    venvpath="$(which python 2>/dev/null)"
+    venvpath="${venvpath%/bin/python}"
+
+    if [[ -z "$venvpath" ]] || [[ "$venvpath" == "/usr" ]]; then
+        return
+    fi
+
+    relative="$(realpath --relative-to="$(pwd)" -s "$venvpath")"
+    venvpath="$(shortest "$venvpath" "$relative")"
+
+    if [[ "$venvpath" == ".venv" ]]; then
+        venvpath=""  # No need to tell me my venv is in .venv, I can guess it.
+    fi
+
+    read -r _ pyversion <<<"$(python --version)"
+
+    printf "$1" "$(trim "$venvpath $pyversion")"
+}