1 Introduction

Background: find command is very useful, especially in the lookup file, this time need to be used with file wildcards.

1 Introduction

Why do we have to learn to use the find command?

Each operating system has thousands of files, for "everything is a file" linux operating system so it is no exception, everyone should be able to easily use the files in windows search function, but on linux it a function may not be very familiar with.

In fact, want to play linux you but also to firmly grasp this command because linux like windows that have a fixed file name suffix, and because the characteristics of the contending camps under linux, the same file in a different releases, there may be different , so if you can firmly grasp the use of the find command you in the dark on the road will be a lot of linux smoothly, and you'll find under linux file search function is very simple, and than find the windows powerful lot! Well, the following entry to the topic

2 find introduction

Command to find files in Linux there are two: the locate and find

First, referring to the next locate, locate the command is traversed (generated database command: it generated database updatedb) , decide to use this feature to find files quickly locate speed, but locate the file command only fuzzy matching, in the accuracy is worse, a brief introduction of the two options under it:

  #locate 

        -i // find files when not case-sensitive, such as: the locate passwd -i 

       -n // Find the results only show the first N lines such as: locate -n 5 passwd

The following focus on that the Find, the Find in without specifying a directory lookup is to traverse the entire system to find

2.1 Syntax

Using the format :

 find [specify lookup directory] [lookup rules] [look after the implementation of the action]

[Specify lookup directory ] For example :

ps: to note here is to use the space between separate directory

Find Rules 2.2

[Find Rules ]

(1) Find the file name

# -Name // Find the file name (pinpoint) 

 # -iname // Find the file name, but not case sensitive

Here we introduce additional knowledge at the file name wildcard

* Indicates a wildcard character in any

? It represents a single arbitrary character wildcard

[] Represents any one wildcard character in brackets

( 2) based on user and group file belongs to locate the file

# -User // according to the owner to find the file 

 # -group // to find is a group based on file

( 3) According to the uid and gid to find a user

 #find  /tmp  -uid  500  //查找uid是500 的文件

 #find  /tmp  -gid  1000 // 查找gid是1000的文件

（4）-a and -o and –not的使用

ps：有用

# -a 连接两个不同的条件（两个条件必须同时满足）

# -o 连接两个不同的条件（两个条件满足其一即可）

# -not 对条件取反的

（5）根据文件时间戳的相关属性来查找文件

我们可以使用stat命令来查看一个文件的时间信息 如下：

           #-atime

           #-mtime

           #-ctime

           #-amin

           #-mmin

           #-cmin

所以这里atime,mtime,ctime就是分别对应的“最近一次访问时间”“最近一次内容修改时间”“最近一次属性修改时间”，这里的atime的单位指的是“天”，amin的单位是分钟

#find /tmp –atime +5 //表示查找在五天内没有访问过的文件（也就是5天前天没访问的文件）

#find /tmp -atime -5 //表示查找在五天内访问过的文件

ps：在清理日志的时候，一般使用的是——最近一次内容修改的时间

find -mtime +30 -name "*[0-9]*" -exec rm {} \;

（6）根据文件类型来查找文件

          -type

                      f     // 普通文件

                      d     //目录文件

                      l     //链接文件

                      b     //块设备文件

                      c     //字符设备文件

                      p     //管道文件

                      s     //socket文件

（7）根据大小来查找文件

-size

#find /tmp -size 2M //查找在/tmp 目录下等于2M的文件

#find /tmp -size +2M //查找在/tmp 目录下大于2M的文件

#find /tmp -size -2M //查找在/tmp 目录下小于2M的文件

（8）根据文件权限查找文件

-perm

#find /tmp -perm 755 //查找在/tmp目录下权限是755的文件

#find /tmp -perm +222 //表示只要有一类用户（属主，属组，其他）的匹配写权限就行

#find /tmp -perm -222 //表示必须所有类别用户都满足有写权限

（9）-nouser and -nogroup

#find / -nogroup –a –nouser //在整个系统中查找既没有属主又没有属组的文件（这样的文件通常是很危险的，作为系统工程师的我们应该及时清除掉）

2.3 [查找完执行的action]

         # -print                                 //默认情况下的动作

         # -ls                                     //查找到后用ls 显示出来

         # -ok  [commend]                //查找后执行命令的时候询问用户是否要执行

        # -exec [commend]              //查找后执行命令的时候不询问用户，直接执行

这里要注意{}的使用：替代查找到的文件

#删除查找到的超过30天没有访问过文件  
find  /tmp  -atime  +30  –exec rm –rf  {}  \；

我们也可以使用xargs来对查找到的文件进一步操作

………………………………………………………………………………………ok! 以上就是关于find的使用方法，排版有点失败，主要是字体调粗后无法调细了，悲催……但是希望各位读者看完这边博客后能有所收获…

3 补充知识

1.删除文件命令：

find 对应目录 -mtime +天数 -name "文件名" -exec rm -rf {} \;

实例命令：

find /opt/soft/log/ -mtime +30 -name "*.log" -exec rm -rf {} \;

说明：

将/opt/soft/log/目录下所有30天前带".log"的文件删除。具体参数说明如下：

find：linux的查找命令，用户查找指定条件的文件；

/opt/soft/log/：想要进行清理的任意目录；

-mtime：标准语句写法；

+30：查找30天前的文件，这里用数字代表天数；

"*.log"：希望查找的数据类型，"*.jpg"表示查找扩展名为jpg的所有文件，"*"表示查找所有文件，这个可以灵活运用，举一反三；

-exec：固定写法；

rm -rf：强制删除文件，包括目录；

{} \; ：固定写法，一对大括号+空格+\+;

Use and summarized under linux find command