linux shell，shell


题记：来源与网络和自己工作中总结。有些脚本片段，函数经常使用。

 

1.判断登录用户

1.1脚本

[devtac@test_1 shell]$ vi check_user.sh

#! /bin/sh

echo "You are logged in as `whoami`";

if [ `whoami` != devtac ]; then
  echo "Must be logged in as devtac to run this script."
  exit
fi

echo "Running script at `date`"

1.2运行结果

[devtac@test_1 shell]$ chmod a+x check_user.sh 
[devtac@test_1 shell]$ ./check_user.sh 
You are logged in as devtac
Running script at 2014年 12月 09日 星期二 13:35:17 CST

 2.判断是否继续执行

2.1脚本

[devtac@test_1 shell]$ vi do_continue.sh

#! /bin/sh

doContinue=n
echo "Do you really want to continue? (y/n)"
read doContinue

if [ "$doContinue" != y ]; then
   echo "Quitting..."
   exit
fi

echo "OK... we will continue."

2.2运行结果

[devtac@test_1 shell]$ ./do_continue.sh 
Do you really want to continue? (y/n)
y
OK... we will continue.
[devtac@test_1 shell]$ ./do_continue.sh 
Do you really want to continue? (y/n)
n
Quitting...
[devtac@test_1 shell]$

 3 隐藏输入

 3.1 脚本

[devtac@test_1 shell]$ vi hide_input.sh

#! /bin/sh

stty -echo
echo -n "Enter the database system password:"
read pw
stty echo


echo "$pw was entered"

3.2 结果

 ./hide_input.sh 
Enter the database system password:123qweasd was entered
[devtac@test_1 shell]$

3.3 解析

stty 命令 

3.3.1 man 手册定义

DESCRIPTION
       Print or change terminal characteristics.

[devtac@test_1 shell]$ stty -a
speed 38400 baud; rows 47; columns 125; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; start = ^Q; stop = ^S;
susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts -cdtrdsr
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff -iuclc -ixany -imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke

 

本例中使用的参数

       [-]echo
              echo input characters

屏蔽显示
stty -echo #禁止回显
stty echo #打开回显
测试方法:
stty -echo;read;stty echo;read

简述： 使用stty -echo 的效果 就像我们输入linux 登录密码时，看不到输入

 

 

 

网络参考：

http://www.ha97.com/4020.html

http://blog.csdn.net/tianlesoftware/article/details/5381984

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