shell for 循环实践

for循环语法结构如下

[root@backup tmp]# cat 1.sh 
#!/bin/bash
for i in `seq 3`
do
    echo $i
done
[root@backup tmp]# sh 1.sh 
1
2
3

批量修改文件名

[root@backup tmp]# ll *.txt
-rw-r--r-- 1 root root 0 May 11 21:34 1.txt
-rw-r--r-- 1 root root 0 May 11 21:34 2.txt
-rw-r--r-- 1 root root 0 May 11 21:34 3.txt
-rw-r--r-- 1 root root 0 May 11 21:34 4.txt
-rw-r--r-- 1 root root 0 May 11 21:34 5.txt
[root@backup tmp]#
[root@backup tmp]# cat 2.sh
#!/bin/bash
cd /tmp
for filename in `ls|grep "txt$"`
do
mv $filename `echo $filename |cut -d . -f1`.gif

done
[root@backup tmp]# sh 2.sh
[root@backup tmp]# ll
total 8
-rw-r--r-- 1 root root 0 May 11 21:34 1.gif
-rw-r--r-- 1 root root 49 May 11 21:33 1.sh
-rw-r--r-- 1 root root 0 May 11 21:34 2.gif
-rw-r--r-- 1 root root 115 May 11 21:39 2.sh
-rw-r--r-- 1 root root 0 May 11 21:34 3.gif
-rw-r--r-- 1 root root 0 May 11 21:34 4.gif
-rw-r--r-- 1 root root 0 May 11 21:34 5.gif

create table t1 (id int(4),name varchar(10)); 

insert into t1(id,name) values (1,'martin');

分库备份mysql数据库

[root@lnmp01 ~]# cat 1.sh
#!/bin/bash
PATH="application/mysql/bin:$PATH"
DBPATH=/server/backup
MYSQLROOT=root
MYPASS=hello123
SOCKET=/tmp/mysql.sock
MYCMD="mysql -u$MYSQLROOT -p$MYPASS -S $SOCKET"
MYDUMP="mysqldump -u$MYSQLROOT -p$MYPASS -S $SOCKET"

[ ! -d $DBPATH ]&& mkdir -p $DBPATH

for dbname in `$MYCMD -e "show databases;"|sed '1,2d'|egrep -v "mysql|schema"` #获取数据库名
do
$MYDUMP $dbname |gzip >$DBPATH/${dbname}_$(date +%F).sql.gz
done
[root@lnmp01 ~]#
[root@lnmp01 ~]# sh 1.sh
[root@lnmp01 ~]# ll /server/backup/
total 12
-rw-r--r-- 1 root root 680 Sep 20 12:16 discusz_2017-09-20.sql.gz
-rw-r--r-- 1 root root 7693 Sep 20 12:16 wordpress_2017-09-20.sql.gz