Bash script for avoid parallel executions

solo.sh

#!/bin/bash
#####################################################################
# Script to ensure that a cmd does not have parallel executions.
#####################################################################

unset LOCKFILE

while getopts l: flag; do
  case $flag in
      l)
        LOCKFILE=$OPTARG
        shift; shift
        ;;
  esac
done

if [ -z "$LOCKFILE" ]; then
    echo "usage: solo -l lockfile cmdline"; echo
    echo "   lockfile  The lockfile to use (e.g. /tmp/mylock)"; echo
    echo "   cmdline   The cmdline to run solo"; echo
    exit 1
fi

# Use BASH's builtin 'noclobber' trick to test the lockfile
if ( set -o noclobber; echo $$ > "$LOCKFILE") 2>/dev/null; then
    # set trap to remove the lockfile on exit
    trap 'rm -f "$LOCKFILE" >/dev/null 2>&1' 0

    # handle non-std termination by returning status=2
    trap 'exit 2' 1 2 3 15

    # eval all arguments passed to us
    eval "$*"
    
else
    OTHERPID=$(cat $LOCKFILE 2>/dev/null)
    if ps -A | cut -f1 -d' ' | grep $OTHERPID >/dev/null 2>&1; then
      echo "Lockfile exists: $LOCKFILE owned by: $OTHERPID "
    else
      echo "Detected stale lockfile, removing for next run .." 
      rm -rf "$LOCKFILE" >/dev/null 2>&1
    fi

fi