linux-shell編程12：shell腳本控制語句

控制語句應用

shell支持的控制語句有break,continue,exit,shift

• shift

  shift的作用是將位置參數參數左移一位，每執行一次shift，$2將變爲$1,依次類推
  [root@server0 programe]# chmod u+x shift.sh
  [root@server0 programe]# ./shift.sh one two three four five six seven eight
  one
  two
  three
  four
  five
  six
  seven
  eight
  [root@server0 programe]# cat shift_.sh
  #!/bin/bash
  for i in $@
  do
  echo $1
  shift
  done
  [root@server0 programe]#

• continue用來在for,while，until循環中使用當前循環中斷執行，進入下一次循環
• break，終止整個for,while,until循環

• exit用來結束腳本的運行

  [root@server0 programe]# cat con_p.sh
  #!/bin/bash
  for num in {1..100}
  do
  case $num in
  1)
  continue
  ;;
  5)
  break
  ;;
  esac
  echo ${num}
  done
  sleep 5
  exit
  echo "……………………………………………………"
  [root@server0 programe]#