Linux下通过find命令进行rm文件删除的小技巧

  

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：

[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：

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

   [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

   [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

2. 測试单独模拟运行脚本中的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 ~]#
   

   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

3. 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：
   

   [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

4. 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：

1. 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
2. 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. 

3. 測试操作确认改动为：
   

   [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放在全部其它參数的前面

解决结果【完毕】