循环语句

用for循环语句的时候，如果不带参数，则表示从命令行取参数，如

#!/bin/sh
for params
do
    echo "You supplied $params as a command line option"
#    echo $params
done

#for params等同于for params in "$@" ,取命令行参数

运行 为 $forparam2.sh myfile1 myfile2

You supplied myfile1 as a command line option
You supplied myfile2 as a command line option


用命令行做参数查找指定文件

#!/bin/sh
for loop
do
    find / -name $loop -print
done

运行$forfind passwd myfile

until循环

$pg until_who

#!/bin/sh

IS_ROOT=`who | grep root`

until [ "$IS_ROOT" ]

do

　　sleep $

done

echo "Watch it.roots in " | mail simon

这段脚本不断的搜寻who命令中的用户root,变量IS-ROOT保存grep命令结果，并向用户simon发送邮件，通知他用户root已经登录。

while循环

设有一文本文件

$more whileread

Louise Conrad:Accounts:ACC8987
Peter James:Payroll:PR489
Fred Terms:Customer:CUS012
James Lenod:Accounts:ACC887
Frank Pavely:Payroll:PR489  

用while循环读取每行

more whileread.sh

#!/bin/sh
while read LINE
do
    echo $LINE
done < names.txt