Teroos.sh -- Runs a bash script for..ever... until stopped

teroos.sh

#!/bin/bash
# teroos - Runs a script for..ever... until stopped

set -eo pipefail

USAGE() {
        echo "Usage: $0 <start|stop|status|install|uninstall> /path/to/script.sh"
    exit
}

[ $# -eq 0 ] && USAGE

# Operations
while [ $# -gt 0 ]; do
        case $1 in
                start)
                        ACTION="run"
                        SCRIPT=$2
                        shift
                        shift
                ;;
                stop)
                        ACTION="stop"
                        SCRIPT=$2
                        shift
                        shift
                ;;
                status)
                        ACTION="info"
                        SCRIPT=$2
                        shift
                        shift
                ;;
                install)
                        ACTION="install"
                        SCRIPT=$2
                        shift
                        shift
                ;;
                uninstall)
                        ACTION="uninstall"
                        SCRIPT=$2
                        shift
                        shift
                ;;
                *)
                        echo "Operation $1 not found"
                        USAGE
                        exit 1
                ;;
        esac
done

TPATH=/tmp/teroos
[ ! -d $TPATH ] && mkdir -p $TPATH

REALPATH=$(realpath $SCRIPT)
BASENAME=$(basename $REALPATH)
PIDFILE=$TPATH/${BASENAME}.pid

case $ACTION in
        run)
                if [ -f $PIDFILE ]; then
                        echo "$BASENAME is running for..ever..."
                        exit 0
                else
                        echo "Running $BASENAME forever..."
                        while :; do eval bash $REALPATH; wait; done > /dev/null 2>&1 & echo $! > $PIDFILE
                fi
        ;;
        stop)
                if      [ ! -f $PIDFILE ]; then
                        echo "$BASENAME is not running"
                        exit 0
                fi

                echo "Killing $BASENAME with PID $(cat $PIDFILE)..."
                kill -SIGTERM $(cat $PIDFILE) && rm $PIDFILE && echo "Done"             
        ;;
        info)
                if [ -f $PIDFILE ]; then
                        echo "$BASENAME is running fine (hopefully) with PID $(cat $PIDFILE)"
                else
                        echo "$BASENAME is not running yet. Run it with [start] operator."
                fi
        ;;
        install)
                # Install script to run as systemd service, so it will run at startup
                if [ "$EUID" -ne 0 ]
                  then echo "Please run as root to install as systemd service"
                  exit
                fi

                echo "Installing $BASENAME as systemd service..."

                spath=$(realpath $0)

                read -p "Creating ${BASENAME}.service, Are you sure? " -n 1 -r
                echo    # (optional) move to a new line
                if [[ ! $REPLY =~ ^[Yy]$ ]]; then
                    exit 1
                fi

                cat << EOF > /etc/systemd/system/${BASENAME}.service
                [Unit]
                Description= $BASENAME service

                [Service]
                ExecStart=$spath start $REALPATH
                ExecStop=$spath stop $REALPATH
                Restart=always
                PIDFile=$PIDFILE

                [Install]
                WantedBy=default.target
EOF
                # Strip leading & trailing whitespaces
                sed -i 's/^[ \t]*//;s/[ \t]*$//' /etc/systemd/system/${BASENAME}.service

                echo "Reloading systemd daemon"
                systemctl daemon-reload && echo "Done"

                echo "You can now start $BASENAME as service, via systemctl <start|stop|status|...> "
        ;;
        uninstall)
                if [ "$EUID" -ne 0 ]
                  then echo "Please run as root to install as systemd service"
                  exit
                fi

                systemctl stop $BASENAME
                systemctl disable $BASENAME
                rm /etc/systemd/system/${BASENAME}.service
                systemctl daemon-reload
                systemctl reset-failed
                echo "Uninstall ${BASENAME}.service done"
        ;;
esac