shell script基础(五)

xuhuojun

(3)for语句
for语法有两种
语法1：
for var in list
do
  commands
done
语法2：
for var
do
  commands
done

例3：for应用范例
[jun_xu@www ~]$ vi for_test
#!/bin/bash
for file in *.txt            //对目录中的每一个txt文件
do
echo "**************************************"
echo $file                 //显示文件名称
echo "**************************************"
cat $file                  //显示文件内容
done

[jun_xu@www ~]$ for_test
**************************************
myrouter.txt
**************************************
#!/bin/bash
my_router=$PWD
echo $my_router

**************************************
readme.txt
**************************************

(4)while及until语句
语法：
while expression            //当expression为真
do
  commands              //执行这些动作
done

until expression            //当expression为假
do
  commands              //执行这些动作
done

(5)break及continue语句
while expression1
do
  while expression2                        
  do
  :
   continue 2
  :
  done
done

例4：范例综合应用
[jun_xu@www ~]$ vi jobcontrol
#!/bin/bash
for x in a b c d e f g h i
do
  for y in 1 2 3 4 5 6 7 8 9
  do
     echo "current job is $x$y"
     echo "input 'n' to do next job"
     echo "      's' to skip the other jobs in current level"
     echo "      'x' to terminate all jobs"
     read action
     if [ $action = n ]
     then
        echo "do next job"
        continue
     elif [ $action = s ]
     then
       echo "skip the other jobs in current level"
       continue 2
     elif [ $action = x ]
     then
       echo "terminate all jobs"
       break 2
     fi
   done
done
[jun_xu@www ~]$ chmod u+x jobcontrol
[jun_xu@www ~]$ ./jobcontrol
current job is a1
input 'n' to do next job
      's' to skip the other jobs in current level
      'x' to terminate all jobs
n
do next job
current job is a2
input 'n' to do next job
      's' to skip the other jobs in current level
      'x' to terminate all jobs
s
skip the other jobs in current level
current job is b1
input 'n' to do next job
      's' to skip the other jobs in current level
      'x' to terminate all jobs
x
terminate all jobs
You have new mail in /var/spool/mail/jun_xu


本文来自ChinaUnix博客，如果查看原文请点：http://blog.chinaunix.net/u1/56188/showart_467248.html