利用选项读行

#!/bin/bash
let i=0
while getopts ":n" SWITCH; do
  case $SWITCH in
     n) let i=1
     ;;
    \?) echo "`basename $0 [-n]`  option"
    ;;
  esac
done
shift $[$OPTIND-1]
let LINENUM=0
 while read line; do
    if [ $i -eq 1 ]; then
       echo "$LINENUM $line"
       let LINENUM++
    else
       echo "$line"
      fi
  done < $1