Posted on 2022-09-24, in Unix, tagged with bash

Minimal bash prompt

When I got into Unix, I made myself the ultimate bash prompt, with several modules each in its own file included from .bashrc. When all are active (what I usually did) they show:

• time
• user
• host
• git/svn status (colors for uncomitted/ unpushed changes, branch)
• Jobs
• Return code of previous command
• In some configurations even SHLVL
• If I'm in SSH
• the python virtual env I'm in
• Current python virtual Environment
• The Id that the next command will have in history in case I want to reuse it with !42

I've been using this for 10 years and then I stumbled upon someone on twitter who said ; is enough. Thinking about that, I realized that I never really use all the information but it takes some time to generate on EVERY command. (And on raspberries, the git prompt takes a loong time)

So now my bash prompt looks like this:

I previously had an alias alias ?="git status" which I used all the time. So now my bash prompt does nothing and is instantaneous, and my ? command tells me everything.

alias ?="_status"
function _status() {
    local bold="\e[1m"
    local red="\e[1;31m"
    local clear="\e[0m"

    if [[ $(jobs |wc -l ) -gt 0 ]]
    then
        echo -e "${bold}Jobs${clear}"
        jobs
    fi

    if [ -n "$VIRTUAL_ENV" ]
    then
        echo -ne"${bold}VENV${clear}    "
        echo "$VIRTUAL_ENV"
    fi

    if [ -n "$SSH_CLIENT" ]
    then
        echo -ne "${bold}SSH${clear}   "
        echo "$SSH_CONNECTION"
    fi

    echo -en "${bold}ID${clear}      "
    [ "$USER" == root ] && echo -ne ${red}
    echo -e $USER${clear}@$HOSTNAME

    if [ -r /sys/class/power_supply/BAT0/ ]
    then
        echo -en "${bold}BATTERY${clear} "
        full=`cat /sys/class/power_supply/BAT0/energy_full`
        now=`cat /sys/class/power_supply/BAT0/energy_now`
        echo -n "$((now*100/full))% "
        cat /sys/class/power_supply/BAT0/status
    fi

    if   git rev-parse &>/dev/null
    then
        echo -e "${bold}GIT${clear}"
        git status -bs --show-stash --ahead-behind -M
        git stash list
    fi

    echo -en "${bold}PWD${clear}     "
    echo  "$PWD"
}

I set this up 3 months ago and am quite happy with it.