标签：ase shell err offline led cat 流程 st3 www
linux shell脚本中流程控制语句 if、for、while、case
1、if语句
[root@centos7 test2]# ls
test.sh
[root@centos7 test2]# pwd
/home/test2
[root@centos7 test2]# cat test.sh
#!/bin/bash
DIR="/home/test2/test3/test4"
if [ ! -e $DIR ]
then
mkdir -p $DIR
echo "new file" > $DIR/new.file
fi
[root@centos7 test2]# bash test.sh
[root@centos7 test2]# ls
test3 test.sh
[root@centos7 test2]# tree
.
├── test3
│ └── test4
│ └── new.file
└── test.sh
2 directories, 2 files
[root@centos7 test2]# cat ./test3/test4/new.file
new file
2、if
[root@centos7 test2]# ls
a.txt test.sh
[root@centos7 test2]# cat a.txt
1
2
3
4
5
[root@centos7 test2]# cat test.sh
#!/bin/bash
num=$(wc -l a.txt | awk ‘{print $1}‘)
tail=$(tail -n 1 a.txt)
if [ $num -eq 5 ] && [ $tail -eq 5 ]
then
echo "right!"
else
echo "error!"
fi
[root@centos7 test2]# bash test.sh
right!
[root@centos7 test2]# echo "6" >> a.txt
[root@centos7 test2]# cat a.txt
1
2
3
4
5
6
[root@centos7 test2]# bash test.sh
error!
3、if
[root@centos7 test2]# ls
test.sh
[root@centos7 test2]# cat test.sh
#!/bin/bash
ping -c 3 -w 6 $1 &> /dev/null
if [ $? -eq 0 ]
then
echo "$1 is online!"
else
echo "$1 is offline!"
fi
[root@centos7 test2]# bash test.sh 192.168.3.59
192.168.3.59 is online!
[root@centos7 test2]# bash test.sh 192.168.3.70
192.168.3.70 is offline!
[root@centos7 test2]# bash test.sh www.baidu.com
www.baidu.com is online!
4、if
[root@centos7 test2]# ls
test.sh
[root@centos7 test2]# cat test.sh
#!/bin/bash
read -p "please input your score: " SCORE
if [ $SCORE -ge 90 ] && [ $SCORE -le 100 ]
then
echo "excellent!"
elif [ $SCORE -ge 60 ] && [ $SCORE -lt 90 ]
then
echo "pass!"
elif [ $SCORE -ge 0 ] && [ $SCORE -lt 60 ]
then
echo "failure!"
else
echo "out of the range! the range is 0-100"
fi
[root@centos7 test2]# bash test.sh
please input your score: 97
excellent!
[root@centos7 test2]# bash test.sh
please input your score: 86
pass!
[root@centos7 test2]# bash test.sh
please input your score: 34
failure!
[root@centos7 test2]# bash test.sh
please input your score: 342
out of the range! the range is 0-100
[root@centos7 test2]# bash test.sh
please input your score: -342
out of the range! the range is 0-100
5、for语句
[root@centos7 test2]# cat a.txt
abcde02
abcde03
abcde04
abcde05
abcde06
abcde07
[root@centos7 test2]# cat test.sh
#!/bin/bash
read -p "please input the passwd: " PASSWD
for i in `cat a.txt`
do
id $i &> /dev/null
if [ $? -eq 0 ]
then
echo "$i had existed!"
else
useradd $i &> /dev/null
echo $PASSWD | passwd --stdin $i &> /dev/null
if [ $? -eq 0 ]
then
echo "$i had created successfully!"
else
echo "$i created failed!"
fi
fi
done
[root@centos7 test2]# bash test.sh
please input the passwd: abc123456
abcde02 had created successfully!
abcde03 had created successfully!
abcde04 had created successfully!
abcde05 had created successfully!
abcde06 had created successfully!
abcde07 had created successfully!
[root@centos7 test2]# userdel -r abcde03
[root@centos7 test2]# userdel -r abcde04
[root@centos7 test2]# userdel -r abcde05
[root@centos7 test2]# bash test.sh
please input the passwd: abc123456
abcde02 had existed!
abcde03 had created successfully!
abcde04 had created successfully!
abcde05 had created successfully!
abcde06 had existed!
abcde07 had existed!
[root@centos7 test2]# for i in `cat a.txt`; do userdel -r $i; done
6、for语句
[root@centos7 test2]# ls
a.txt test.sh
[root@centos7 test2]# cat a.txt
www.baidu.com
www.xxxxxxyyy.com
www.taobao.com
www.jjjjjjxxxxx.com
www.jd.com
www.tencent.com
11111111
[root@centos7 test2]# cat test.sh
#!/bin/bash
for i in `cat a.txt`
do
ping -c 3 -w 6 $i &> /dev/null
if [ $? -eq 0 ]
then
echo "$i is online!"
else
echo "$i is offline!"
fi
done
[root@centos7 test2]# bash test.sh
www.baidu.com is online!
www.xxxxxxyyy.com is offline!
www.taobao.com is online!
www.jjjjjjxxxxx.com is offline!
www.jd.com is online!
www.tencent.com is online!
11111111 is offline!
linux shell脚本中流程控制语句 if 、for、while、case
标签：ase shell err offline led cat 流程 st3 www
原文地址：https://www.cnblogs.com/liujiaxin2018/p/14687470.html
