Linux下通过find命令进行rm文件删除的小技巧
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我们常常会通过find命令进行批量操作。如：批量删除旧文件、批量改动、基于时间的文件统计、基于文件大小的文件统计等。在这些操作其中，因为rm删除操作会导致文件夹结构变化，假设要通过find结合rm的操作写成脚本。就会遇到一些麻烦，本文通过一个样例为大家进行介绍。
系统环境：
SUSE Linux Enterprise Server 11 或
Red Hat Enterprise Linux
问题症状：
客户现场有一个自己主动化的脚本，有下面的find语句，每天执行以删除某个文件夹下7天曾经的文件或文件夹，这些文件夹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 ‘{}‘ \;
执行过程中。间歇性地出现下面错误：[[email protected] ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/rm -rf {} \; /bin/find: `/enterprisedb_backup/postgresql/network-scripts‘: No such file or directory [[email protected] ~]# echo $? 1
显然，以上命令返回了错误的结果，但客户反映说，以上脚本执行后文件夹下7天前的数据的确备删除了。
问题分析：
进行故障重现。在还有一台server中通过模拟数据单独执行find命令分析此问题。測试步骤例如以下：
- 模拟数据
[[email protected] ~]# date Wed Jun 18 23:08:18 CST 2014 [[email protected] ~]# cp -rcp /etc/sysconfig/network-scripts/ /enterprisedb_backup/postgresql/ [[email protected] ~]# cp -rcp /etc/init.d/iptables /enterprisedb_backup/postgresql/
## 以上通过 cp -rcp 命令使得复制到目标文件夹的数据保持包含：建立时间、用户权根等信息，以模拟出一个旧文件及一个旧文件夹
[[email protected] ~]# 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
## 以上能够看到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
[[email protected] ~]# 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
## 以上能够看到network-script不是一个空的文件夹，其中还有文件，并且文件也都已经是7天前建立的了
-
測试单独模拟运行脚本中的find + rm指令
[[email protected] ~]# /bin/find /enterprisedb_backup/postgresql/ -mtime +7 -exec /bin/rm -rf {} \; /bin/find: `/enterprisedb_backup/postgresql/network-scripts‘: No such file or directory [[email protected] ~]# echo $? 1 [[email protected] ~]# ls /enterprisedb_backup/postgresql/ [[email protected] ~]#
能够看到find操作的确返回了错误的结果，但查看数据备份文件夹发现，iptables文件及network-scripts文件夹已经正确删除
- 因为数据已经正确删除，因此我们開始怀疑是由network-scripts文件夹删除后。find继续尝试删除此文件夹下其他文件。导致出不“No such file or directory”的错误。因此须要于进一步证实此猜想。又一次运行以上“第1步”中的数据环境模拟。并运行下面操作，主要是将rm转换成ls以展现总体运行过程：
[[email protected] ~]# cp -rcp /etc/sysconfig/network-scripts/ /enterprisedb_backup/postgresql/ [[email protected] ~]# cp -rcp /etc/init.d/iptables /enterprisedb_backup/postgresql/ [[email protected] ~]# /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
通过以上操作我们能够看到。find命令不单查询了/enterprisedb_backup/postgresql/文件夹，而且遍历了全部子文件夹。因此支持了我们的判断
- 综上所述基本定位问题所在
分析图解：
这个图不知让咋画
解决方式：
- 整理思路后，能够确认，假设find仅仅找出所需操作文件夹的第1层文件及文件夹就可以解决此问题
- 通过伟大的 man 命令我们得到下面信息
-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.
- 測试操作确认改动为：
[[email protected] ~]# /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放在全部其它參数的前面
解决结果【完毕】
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