bash option parsing

Since I know I’m going to forget how to do it properly, this is a tiny recipe to easily parse options in bash. I use getopts (and not getopt . !!! mind the S) that is a builtin shell command. help getopts to read the doco.

The snippet is pretty easy and self explanatory :

#!/bin/bash

usage()
{
DESCRIPTION=
cat << EOF
usage: $0 options

$DESCRIPTION

OPTIONS:
   -h      Show this message
   -v      Verbose
   -d      Debug
   -f      file
EOF
}

VERBOSE=
DEBUG=
FILE=
OTHERARGS=

while getopts "vhdf:" flag
do
  case "$flag" in
    f) FILE=$OPTARG ;;
    d) set -x ; DEBUG=true;;
    v) VERBOSE=true ;;
    h) usage ; exit 0 ;;
  esac
#  echo "$flag" $OPTIND $OPTARG
done

if [ -z $FILE ]; then
  shift $((OPTIND-1))
  OTHERARGS="$@"
fi

if [ -n "$VERBOSE"] ; then
  echo "verbose $VERBOSE"
  echo "debug $DEBUG"
  echo "file $FILE"
  echo "other args $OTHERARGS"
fi

exit 0