Use '' and not " to quote the string. This allows to use " inside without escaping

gistfile1.txt

{stdenv, bash, jre, spark} :

stdenv.mkDerivation rec {
   name = "mesos-spark-${version}";
   version = "1";
   
   unpackPhase = "true";
   
installPhase = ''
    set -x
    mkdir -p $out/bin

    cat > $out/bin/mesos-spark-shell <<EOF
    #!${bash}/bin/bash
    set -o posix
    export JAVA_HOME=${jre}
    export SPARK_HOME=${spark}/lib/spark-1.0.1-bin-cdh4

    for o in "\$@"; do
      if [ "\$1" = "-c" -o "\$1" = "--cores" ]; then
        shift
        if [ -n "\$1" ]; then
          OPTIONS="-Dspark.cores.max=\$1"
          shift
        fi
      fi
    done

EOF
    chmod +x $out/bin/mesos-spark-shell
''; 
}