Shell 编程 until语句

本篇主要写一些shell脚本until语句的使用。

---

#!/bin/bash i=0 s=0 until [ $i -eq 51 ];do   let s+=i;let i++ done echo $s

[root@localhost ~]# vim sum.sh [root@localhost ~]# chmod +x sum.sh  [root@localhost ~]# ./sum.sh  1275

#!/bin/bash username=$1 # 判断格式是否正确 if [ $# -lt 1 ] ;then   echo "Usage:`basename $0` <username> [message]"   exit 1 fi # 判断用户是否存在 if grep "^$username:" /etc/passwd > /dev/null ;then : else   echo "用户不存在"   exit 1 fi # 判断用户是否在线，不在则每5s联系一次 until who|grep "$username" > /dev/null ;do   echo "用户不在线"   sleep 5 done # 发送信息 mes=$* echo $mes | write $username

[root@localhost ~]# vim message.sh [root@localhost ~]# chmod +x message.sh  [root@localhost ~]# ./message.sh  Usage:message.sh <username> [message] [root@localhost ~]# ./message.sh zhangsan hello 用户不存在 [root@localhost ~]# useradd zhangsan && echo "000000" | passwd --stdin zhangsan Changing password for user zhangsan. passwd: all authentication tokens updated successfully. [root@localhost ~]# ./message.sh zhangsan hello 用户不在线 用户不在线 ^C

[zhangsan@localhost ~]$ 

[root@localhost ~]# ./message.sh zhangsan hello

[zhangsan@localhost ~]$  Message from root@localhost on pts/0 at 02:25 ... zhangsan hello EOF

来源：博客园

作者：LinSenGeGe

链接：https://www.cnblogs.com/llife/p/11633413.html