shell实例(二十一) ----stty,命令

1.设置一个擦除字符

#! /bin/sh
echo -n "What is your name? "
read name
echo "Your name is $name"
stty erase '#'                                       ----设置擦除字符为'#'
echo -n "What is your name?"
read name
echo "Your name is $name."
exit 0

 

2.关闭终端对密码的echo

#! /bin/sh
echo
echo -n "Enter password "
read passwd
echo "password is $passwd"
echo -n "If someone had been looking over your shoulder,"
echo "your password would have been compromised."
echo && echo
stty -echo                -----------------关闭echo输出显示
echo -n "Enter password again "
read passwd
echo
echo "password is $passwd"
echo
stty echo
exit 0

 

3.按键检测

#! /bin/sh
echo
old_tty_settings=$(stty -g)
stty -icanon                                ------------------按下一个键，及结束输入
keypress=$(head -c1)                ------------------取输入的第一个字符   
echo
echo "key pressed was /""$keypress"/"."
echo
stty "$old_tty_settings"
exit 0

 

4.获取正在访问某个或某些文件（或目录)的进程ID

 fuser -u /usr/bin/vim

 fuser -um /dev/device_name ---解决umount 一个设备失败的问题

 fuser -n  -----------获得访问某一个端口的进程

 

5.以一个指定的间隔运行某一个命令

watch -n 5 tail /var/log/messages   -----每隔5秒钟显示一下

watch -n 5 echo 'Hello World~'       -----用单引号

 

6.命令替换

 file=`ls -l`  ----------把一个命令的结果放入到一个变量

 echo $file   ----------显示这个变量

aa=$( wc -w $(ls -l | awk '{print $8}'))  ---统计每个文件含有的单词数

 

7.将一个循环放入变量中

 #! /bin/sh
var1=`for i in 1 2 3 4 5
do
 echo -n "$i"
done`
echo $var1

i=0
var2=`while [ "$i" -lt 10 ]
do
 let "i = i+1"
 echo -n "$i"
done`

echo $var2