浅谈Linux下通过find命令进行rm文件删除的小技巧
我们经常会通过find命令进行批量操作，如：批量删除旧文件、批量修改、基于时间的文件统计、基于文件大小的文件统计等，在这些操作当中，由于rm删除操作会导致目录结构变化，如果要通过find结合rm的操作写成脚本，就会遇到一些麻烦，本文通过一个例子为大家进行介绍。
系统环境：
SUSE Linux Enterprise Server 11 或
Red Hat Enterprise Linux
问题症状：
客户现场有一个自动化的脚本，有以下的find语句，每天运行以删除某个目录下7天以前的文件或目录，这些目录都是按时间顺序生成PostgreSQL数据库的WAL日志及其错误日志pg_log：
/bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/rm -rf '{}' ;
运行过程中，间歇性地出现以下错误：
[root@edb ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/rm -rf {} ; /bin/find: `/enterprisedb_backup/postgresql/network-scripts': No such file or directory [root@edb ~]# echo $? 1
显然，以上命令返回了错误的结果，但客户反映说，以上脚本运行后目录下7天前的数据的确备删除了。
问题分析：
进行故障重现，在另一台服务器中通过模拟数据单独运行find命令分析此问题，测试过程如下：
1.模拟数据
[root@edbnode1 ~]# date Wed Jun 18 23:08:18 CST 2014 [root@edbnode1 ~]# cp -rcp /etc/sysconfig/network-scripts/ /enterprisedb_backup/postgresql/ [root@edbnode1 ~]# cp -rcp /etc/init.d/iptables /enterprisedb_backup/postgresql/## 以上通过 cp -rcp 命令使得拷贝到目标目录的数据保持包括：建立时间、用户权根等信息，以模拟出一个旧文件及一个旧目录 [root@edbnode1 ~]# ll /enterprisedb_backup/postgresql/ total 16 -rwxr-xr-x. 1 root root 9409 Oct 31 2012 iptables drwxr-xr-x. 2 root root 4096 Jun 18 2013 network-scripts## 以上可以看到iptables文件是2012年建立的，network-scripts是2013年建立的，都远远超过了7天 [root@edbnode1 ~]# ll /enterprisedb_backup/postgresql/* -rwxr-xr-x. 1 root root 9409 Oct 31 2012 /enterprisedb_backup/postgresql/iptables /enterprisedb_backup/postgresql/network-scripts: total 212 -rw-r--r--. 1 root root 159 Jun 18 2013 ifcfg-eth0 -rw-r--r--. 1 root root 203 Jun 18 2013 ifcfg-eth1 -rw-r--r--. 1 root root 203 Jun 18 2013 ifcfg-eth2 -rw-r--r--. 1 root root 254 Jan 9 2013 ifcfg-lo lrwxrwxrwx. 1 root root 20 Jun 18 2013 ifdown -> ../../../sbin/ifdown -rwxr-xr-x. 1 root root 627 Jan 9 2013 ifdown-bnep -rwxr-xr-x. 1 root root 5397 Jan 9 2013 ifdown-eth -rwxr-xr-x. 1 root root 781 Jan 9 2013 ifdown-ippp -rwxr-xr-x. 1 root root 4168 Jan 9 2013 ifdown-ipv6 lrwxrwxrwx. 1 root root 11 Jun 18 2013 ifdown-isdn -> ifdown-ippp -rwxr-xr-x. 1 root root 1481 Jan 9 2013 ifdown-post -rwxr-xr-x. 1 root root 1064 Jan 9 2013 ifdown-ppp -rwxr-xr-x. 1 root root 835 Jan 9 2013 ifdown-routes -rwxr-xr-x. 1 root root 1370 Jan 9 2013 ifdown-sit -rwxr-xr-x. 1 root root 1434 Jan 9 2013 ifdown-tunnel lrwxrwxrwx. 1 root root 18 Jun 18 2013 ifup -> ../../../sbin/ifup -rwxr-xr-x. 1 root root 12365 Jan 9 2013 ifup-aliases -rwxr-xr-x. 1 root root 859 Jan 9 2013 ifup-bnep -rwxr-xr-x. 1 root root 10157 Jan 9 2013 ifup-eth -rwxr-xr-x. 1 root root 11971 Jan 9 2013 ifup-ippp -rwxr-xr-x. 1 root root 10401 Jan 9 2013 ifup-ipv6 lrwxrwxrwx. 1 root root 9 Jun 18 2013 ifup-isdn -> ifup-ippp -rwxr-xr-x. 1 root root 727 Jan 9 2013 ifup-plip -rwxr-xr-x. 1 root root 954 Jan 9 2013 ifup-plusb -rwxr-xr-x. 1 root root 2364 Jan 9 2013 ifup-post -rwxr-xr-x. 1 root root 4154 Jan 9 2013 ifup-ppp -rwxr-xr-x. 1 root root 1925 Jan 9 2013 ifup-routes -rwxr-xr-x. 1 root root 3499 Jan 9 2013 ifup-sit -rwxr-xr-x. 1 root root 2488 Jan 9 2013 ifup-tunnel -rwxr-xr-x. 1 root root 3770 Jan 9 2013 ifup-wireless -rwxr-xr-x. 1 root root 4623 Jan 9 2013 init.ipv6-global -rwxr-xr-x. 1 root root 1125 Jan 9 2013 net.hotplug -rw-r--r--. 1 root root 13079 Jan 9 2013 network-functions -rw-r--r--. 1 root root 29853 Jan 9 2013 network-functions-ipv6 ## 以上可以看到network-script不是一个空的目录，当中还有文件，而且文件也都已经是7天前建立的了
2.测试单独模拟执行脚本中的find + rm指令
[root@edbnode1 ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/rm -rf {} ; /bin/find: `/enterprisedb_backup/postgresql/network-scripts': No such file or directory [root@edbnode1 ~]# echo $? 1 [root@edbnode1 ~]# ls /enterprisedb_backup/postgresql/ [root@edbnode1 ~]#
可以看到find操作的确返回了错误的结果，但查看数据备份目录发现，iptables文件及network-scripts目录已经正确删除
3.由于数据已经正确删除，因此我们开始怀疑是由network-scripts目录删除后，find继续尝试删除此目录下其它文件，导致出不“No such file or directory”的错误，因此需要于进一步证实此猜想，重新执行以上“第1步”中的数据环境模拟，并执行以下操作，主要是将rm转换成ls以展现整体运行过程：
[root@edbnode1 ~]# cp -rcp /etc/sysconfig/network-scripts/ /enterprisedb_backup/postgresql/ [root@edbnode1 ~]# cp -rcp /etc/init.d/iptables /enterprisedb_backup/postgresql/ [root@edbnode1 ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/ls {} ; ifcfg-eth0 ifcfg-lo ifdown-eth ifdown-isdn ifdown-routes ifup ifup-eth ifup-isdn ifup-post ifup-sit init.ipv6-global network-functions-ipv6 ifcfg-eth1 ifdown ifdown-ippp ifdown-post ifdown-sit ifup-aliases ifup-ippp ifup-plip ifup-ppp ifup-tunnel net.hotplug ifcfg-eth2 ifdown-bnep ifdown-ipv6 ifdown-ppp ifdown-tunnel ifup-bnep ifup-ipv6 ifup-plusb ifup-routes ifup-wireless network-functions /enterprisedb_backup/postgresql/network-scripts/ifup-plusb /enterprisedb_backup/postgresql/network-scripts/ifup-sit /enterprisedb_backup/postgresql/network-scripts/ifdown-post /enterprisedb_backup/postgresql/network-scripts/ifcfg-lo /enterprisedb_backup/postgresql/network-scripts/network-functions /enterprisedb_backup/postgresql/network-scripts/ifup-bnep /enterprisedb_backup/postgresql/network-scripts/ifup-ippp /enterprisedb_backup/postgresql/network-scripts/ifdown-sit /enterprisedb_backup/postgresql/network-scripts/ifdown-tunnel /enterprisedb_backup/postgresql/network-scripts/ifup-plip /enterprisedb_backup/postgresql/network-scripts/ifup-eth /enterprisedb_backup/postgresql/network-scripts/ifdown-ipv6 /enterprisedb_backup/postgresql/network-scripts/ifdown-ippp /enterprisedb_backup/postgresql/network-scripts/ifup-aliases /enterprisedb_backup/postgresql/network-scripts/network-functions-ipv6 /enterprisedb_backup/postgresql/network-scripts/ifup-ipv6 /enterprisedb_backup/postgresql/network-scripts/ifup-post /enterprisedb_backup/postgresql/network-scripts/ifcfg-eth2 /enterprisedb_backup/postgresql/network-scripts/ifcfg-eth1 /enterprisedb_backup/postgresql/network-scripts/ifdown-ppp /enterprisedb_backup/postgresql/network-scripts/ifup-isdn /enterprisedb_backup/postgresql/network-scripts/ifcfg-eth0 /enterprisedb_backup/postgresql/network-scripts/ifdown /enterprisedb_backup/postgresql/network-scripts/ifup-wireless /enterprisedb_backup/postgresql/network-scripts/ifup-ppp /enterprisedb_backup/postgresql/network-scripts/ifdown-eth /enterprisedb_backup/postgresql/network-scripts/init.ipv6-global /enterprisedb_backup/postgresql/network-scripts/ifdown-isdn /enterprisedb_backup/postgresql/network-scripts/ifup-tunnel /enterprisedb_backup/postgresql/network-scripts/ifdown-routes /enterprisedb_backup/postgresql/network-scripts/ifdown-bnep /enterprisedb_backup/postgresql/network-scripts/net.hotplug /enterprisedb_backup/postgresql/network-scripts/ifup /enterprisedb_backup/postgresql/network-scripts/ifup-routes /enterprisedb_backup/postgresql/iptables
通过以上操作我们可以看到，find命令不单查询了/enterprisedb_backup/postgresql/目录，并且遍历了所有子目录，因此支持了我们的推断
4.综上所述基本定位问题所在
解决方案：
1.整理思路后，可以确认，如果find只找出所需操作目录的第1层文件及目录即可解决此问题
2.通过伟大的 man 命令我们得到以下信息
-maxdepth levels Descend at most levels (a non-negative integer) levels of directories below the command line arguments. -maxdepth 0 means only apply the tests and actions to the command line arguments.
3.测试操作确认修改为：
[root@edbnode1 ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -maxdepth 1 -exec /bin/rm -rf {} ; /bin/find: warning: you have specified the -maxdepth option after a non-option argument -mtime, but options are not positional (-maxdepth affects tests specified before it as well as those specified after it). Please specify options before other arguments.
这里意思是说：-mtime找到的信息可能会操过-maxdepth的范围，在find操作中建议-maxdepth放在所有其他参数的前面
解决结果【完成】
以上这篇浅谈Linux下通过find命令进行rm文件删除的小技巧就是小编分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持脚本之家。
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