彩色shell输出:

example:防止密码被偷看

[root@fedora14 ~]# cat 6.sh
#!/bin/bash

echo -e "Please input password...�33[31;41m"
read PASSWD
echo -e "�33[0m"
echo $PASSWD | openssl md5
[root@fedora14 ~]# ./6.sh
Please input password...
fsdfsafsfaf

(stdin)= b8d97575383bdc8a3afe5e30f624461e
[root@fedora14 ~]# 

shell中的数学计算：

[root@fedora14 ~]# expr 6 + 3
9
[root@fedora14 ~]# echo | expr 6 + 3
9
[root@fedora14 ~]# echo | expr 6 / 3
2
[root@fedora14 ~]# echo | expr 6 * 3
expr: syntax error
[root@fedora14 ~]# echo | expr 6 * 3
18
[root@fedora14 ~]# echo | expr 6 % 3
0
[root@fedora14 ~]# 

example1:

[root@fedora14 ~]# find /etc -name "*.conf" | wc -l
337
[root@fedora14 ~]# echo $?
0
[root@fedora14 ~]# cat /etc/httpd.conf2
cat: /etc/httpd.conf2: No such file or directory
[root@fedora14 ~]# echo $?
1
[root@fedora14 ~]# ls /etc/httpd.conff
ls: cannot access /etc/httpd.conff: No such file or directory
[root@fedora14 ~]# echo $?
2
[root@fedora14 ~]# 

example1:

[root@fedora14 ~]# echo "Your name"
Your name
[root@fedora14 ~]# read NAME
xianglou
[root@fedora14 ~]# echo "Hello $NAME,"
Hello xianglou,
[root@fedora14 ~]# echo "Hello $NAME,"
Hello xianglou,
[root@fedora14 ~]# read NAME1 NAME2
aaaaaaaaaaaaaaaaaa
[root@fedora14 ~]# echo $NAME1
aaaaaaaaaaaaaaaaaa
[root@fedora14 ~]# echo $NAME2

[root@fedora14 ~]# read NAME1 NAME2
AAAAAAAAAAAAAAAA BBBBBBBBBBBBBBBBBBB
[root@fedora14 ~]# echo $NAME1
AAAAAAAAAAAAAAAA
[root@fedora14 ~]# echo $NAME2
BBBBBBBBBBBBBBBBBBB
[root@fedora14 ~]# 

example1:

[root@fedora14 ~]# date ;echo " "; cat names 
Thu Apr  5 11:15:20 PDT 2012
 
china   beijing         123
America   NewYork       456
England   London        789
England   London
[root@fedora14 ~]# 

命令行的参数

example1:

[root@fedora14 ~]# cat 7.sh
#!/bin/bash
echo "$0:$0"
echo "$1:$1"
echo "$2:$2"
echo "Total:$#"
echo "$@:$@"
[root@fedora14 ~]# ./7.sh root fedora
$0:./7.sh
$1:root
$2:fedora
Total:2
$@:root fedora
[root@fedora14 ~]# 

shell脚本中的条件判断

    shell的返回结果  0为true,可以理解为没有错误,1为false

example1:

[root@fedora14 ~]# vim 7.sh
#!/bin/bash
if [ 0 ];then
        echo "This is true"
else
        echo "This is false"
fi

[root@fedora14 ~]# ./7.sh
This is true

example1: 用 ping 测试某台主机是否在线

[root@fedora14 ~]# vim 7.sh
#!/bin/bash
HOST=$2
if [ $# -ne 0 -a "$1" == "ok" ];then
        if ping -c2 $HOST&>/dev/null;then
                echo "$HOST is online"
        else
                echo "$HOST is down"
        fi
else
        echo "Please input ....."
fi


[root@fedora14 ~]# ./7.sh ok 192.168.73.50
192.168.73.50 is online
[root@fedora14 ~]# 

example2: 用ping循环测试多台主机是否在线

[root@fedora14 ~]# vim 8.sh
#!/bin/bash
for  TEMP in $@
do
        ping -c2 $TEMP &>/dev/null && echo "$TEMP is online" || echo "$TEMP is down"
done

[fedora@fedora14 ~]$ [ -w ./test.file ] && echo "Files can reading" || echo "Files cannot writing"

case、函数

example1: 显示菜单

#!/bin/bash
showmenu()
{
        echo -e "1.linuxn2.windowsn3.unixn4.quit"
        read IN
}

testchoose()
{
        if [ $IN == "" ];then
                echo "Please input 123"
                exit -1
        else
                case $IN in
                        1)
                                echo "welcome to linux";;
                                #exit 1;;
                        2)
                                echo "welcome to windows";;
                                #exit 2;;
                        3)
                                echo "welcome to unix";;
                                #exit 3;;
                        4)  exit 4;;
                esac
        fi
}

main()
{
        IN=0
        while [ "$IN" != "4"  ]
        do
                showmenu
                testchoose
        done
}

main

example2： 过虑帐户

#!/bin/bash
FILE="/etc/passwd"
test()
{
        if (($1<=0)); then
                echo "Please input...."
        else
                cat $FILE | grep $2
        fi
}
test $# $1

文件测试操作

example1:测试文件是否存在

[root@bogon ~]# [ -e /etc/grub.conf  ] && echo "Files can be reading" || echo "Files cannot reading"
Files can be reading
[root@bogon ~]# [ -e /etc/grub.confa  ] && echo "Files can be reading" || echo "Files cannot reading"
Files cannot reading
[root@bogon ~]# 

example2: