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Bash变量
?变量=值
?引用方式为:$变量
[root@localhost Desktop]# HI="Hello,and welcome to $(hostname)." [root@localhost Desktop]# echo $HI Hello,and welcome to localhost.localdomain. [root@localhost Desktop]#
? &> :重定向所有的输出
? 2>&1 :重定向STDERR到STDOUT
? > :重定向STDOUT
? 2> :重定向STDERR
[root@localhost test]# ll *.sh *.txt > AAA ls: cannot access *.txt: No such file or directory [root@localhost test]# cat AAA -rwxr--r--. 1 root root 158 Jun 28 06:36 test1.sh -rwxrwxrwx. 1 root root 59 Jun 28 06:33 test.sh
[root@localhost test]# ll *.sh *.txt 2> BBB -rwxr--r--. 1 root root 158 Jun 28 06:36 test1.sh -rwxrwxrwx. 1 root root 59 Jun 28 06:33 test.sh [root@localhost test]# cat BBB ls: cannot access *.txt: No such file or directory
[root@localhost test]# ll *.sh *.txt &> CCC [root@localhost test]# cat CCC ls: cannot access *.txt: No such file or directory -rwxr--r--. 1 root root 158 Jun 28 06:36 test1.sh -rwxrwxrwx. 1 root root 59 Jun 28 06:33 test.sh
从文件重定向到标准输入：
[root@localhost test]# cat AAA -rwxr--r--. 1 root root 158 Jun 28 06:36 test1.sh -rwxrwxrwx. 1 root root 59 Jun 28 06:33 test.sh
[root@localhost test]# cat AAA | tr ‘a-z‘ ‘A-Z‘ -RWXR--R--. 1 ROOT ROOT 158 JUN 28 06:36 TEST1.SH -RWXRWXRWX. 1 ROOT ROOT 59 JUN 28 06:33 TEST.SH
[root@localhost test]# tr ‘a-z‘ ‘A-Z‘ <AAA -RWXR--R--. 1 ROOT ROOT 158 JUN 28 06:36 TEST1.SH -RWXRWXRWX. 1 ROOT ROOT 59 JUN 28 06:33 TEST.SH
for语句：
[root@localhost test]# cat for.sh #!/bin/bash for NAME in joe jak sky do MESSAGE=‘hello world‘ echo He name is $NAME. " $NAME say $MESSAGE !" done [root@localhost test]# ./for.sh He name is joe. joe say hello world ! He name is jak. jak say hello world ! He name is sky. sky say hello world ! [root@localhost test]#
[root@localhost test]# cat for1.sh
#!/bin/bash
for num in $(seq 1 6)
do
echo $num
done
[root@localhost test]# ./for1.sh
1
2
3
4
5
6
[root@localhost test]#
[root@localhost test]# cat if.sh #!/bin/bash if ping -c1 -w2 128.0.0.1 &>/dev/null; then echo network service is up ! elif grep network /weihu.txt &>/dev/null; then echo network service is in maintenance ! else echo station is down ! fi [root@localhost test]#
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原文地址：http://www.cnblogs.com/skyfly0772/p/5625420.html
