starter

#!/bin/bash
 
# DEFAULT VALUES
default_output_format='txt'
default_position_column_width=40
 
 
# SUPPORTING FUNCTIONS
function display_usage {
    echo "Usage: `basename $0` [-o (txt|csv)] [-wp <integer>] [-h]"
    echo "  where"
    echo "    -o              : Specifies the output format (txt or csv). Default is '${default_output_format}'."
    echo "    -wp             : Specifies the width of the 'Position' column. Default is ${default_position_column_width}."
    echo "    -h              : Display this usage."
    exit
}
 
 
# ASSIGN DEFAULT VALUES
position_column_width=$default_position_column_width
output_format=$default_output_format
 
 
# GET COMMAND LINE ARGUMENTS
while [ $# -gt 0 ]
do
  case $1
  in
    '-o')
      output_format=$2
      shift 2
    ;;
 
    '-wp')
      position_column_width=$2
      shift 2
    ;;
 
    '-h')
      display_usage
    ;;
 
    *)
      echo "Error: unknown argument '$1'."
      display_usage
    ;;
  esac
done