sleep-countdown

#!/bin/bash 

# Gokberk Cinbis, 2021

# set -e --> DONT! not compatible with wait() usage below (or handle its return signal)

function helpandexit() {
    echo "USAGE: sleep-countdown [--keyinterrupt] <seconds>"
    echo "If --keyinterrupt is given, any keypress immediately stops the countdown."
    exit 1
}

function sleep_countdown_func() {
    local narg=$#

    if [ $narg -eq 1 ]
    then
        secs=$1
        while [ $secs -gt 0 ]; do
            echo -ne "Wait $secs seconds...\033[0K\r"
            sleep 1
            : $((secs--))
        done
    elif [ $narg -eq 2 ]
    then
        # https://linuxhint.com/bash_wait_keypress/
        secs=$2
        if [[ "$1" == "--keyinterrupt" ]]
        then
            :
        else
            echo "sleep-countdown - unrecognized argument: $1"
            exit 2
        fi 
        while [ $secs -gt 0 ]; do
            echo -ne "Wait $secs seconds... (press any key to skip countdown) \033[0K\r"
            command read -t 1 -n 1
            if [ $? = 0 ] ; then
                secs=0
            else
                : $((secs--))
            fi
        done
    else
        helpandexit
    fi
    
    echo -ne "\033[0K\r" # cleanup
    exit 0

}

# ok with multiple quoted arguments
sleep_countdown_func "$@"