simple lockfile mechanism with bash trap

#!/usr/bin/env bash

# simple script to test invoking over ssh and cancelling with ctrl-c to trigger trap cleanup

LOCKFILEPATH="/tmp/signaltest.lock"

function mutex() {
  if [ -f "$LOCKFILEPATH" ]; then
    echo -e "Build already in progress! Exiting.";
    exit 1;
  else
    touch $LOCKFILEPATH;
    trap cleanup EXIT SIGHUP SIGKILL SIGTERM SIGINT;
  fi
}

function gitclone() {
  git clone --branch master git@github.com:bitcoin/bitcoin.git src_$(date +"%s");
}

function cleanup() {
  rm -rf "$LOCKFILEPATH";
}

mutex \
&& gitclone;