"One day one Linux" find usage detailed notes

The Find command is powerful and has many options for finding files, so this is a very useful and common Linux command. But he has a drawback is that the search time is relatively slow. The opposite is a locate command.

1. Command format for Find

Find Pathname-option [-print] [-exec-ok command] {} \;

　　

2. Command parameters:

The directory path that the Pathname:find command looks for. Both relative and absolute paths are available.

The-print:find command outputs the matched file to standard output (the default is to output the found file to standard output)

-exec Command {} \: Find commands to execute command commands given by this parameter to the matching file, note the space between ' {} ' and ' \ '.

-exec OK {} \: Similar to the EXEC command parameter, there is only one more check that requires the user to confirm execution before executing each command.

3. Options for the command:

Common:

-name filename: Finding a file named filename (Common options)

File properties:

-perm xxxx: Follow the XXXX Representative's execution permissions to find

-user Username: Search by file Owner

-group groupname: Search by file group

-nouser find a file without a valid owner, that is, the master does not exist in the/etc/passwd

-nogroup find a file without a valid genus, that is, the master does not exist in the/etc/groups

File Time Properties:

-mtime-n +n In accordance with the file change time to find,-n means n days or less +n refers to n days ago

-atime-n +n Follow the file access time to find

-ctime-n +n Follow the file creation time to find

-newer file1! File2 find change time than file1 new but older than file2 file

File Type properties:

-type finding a file of a certain type

B-Block Device directory

D-Catalog

C-Character device files

P-Piping File

L-Symbolic Link file

F-Normal file

Other types

-size n [C]: Find files with a file length of n blocks, with C indicating that the length of the file is calculated in bytes.

-depth: Find the file first, look for the current directory, and then find its subdirectories.

-fstype: Find files located in a file system of a certain type, these file system types can usually be found in the configuration file/etc/fstab, which contains information about this file system.

-mount: Does not cross the file system mount point when locating files. (This sentence is not too understanding ha, wait for the next example to see.) ）

-follow: If the find command encounters a symbolic link file, it tracks to the file that the link points to.

-cpio: Use the cpio command for matching files to back up these files to the disk device.

-prune: Ignoring a directory

　　

In addition, the following three differences:

-amin N Find the last n minutes of files accessed in the system

　　　　-atime N Find the last n*24 hour Access file in the system

-cmin n Find files in the last n minutes of the system changed file status
-ctime n Find files that have changed file status in the last n*24 hours of the system
-mmin n Find files that have changed file data in the last N minutes of the system
-mtime n Find files that have changed file data for the last n*24 hours in the system

4. Usage examples

(1)-name option

Compare common options, and you can use a match or regular expression to match the file (the difference between the match and the regular is important to note). If a specific file name can be enclosed in quotation marks, you can also use quotation marks, but the file name matching pattern must be enclosed in quotation marks.

　　　　

" Test.txt " of the file Find /-name  "test.txt"  -print

#匹配符与正则表达式的应用:
Find all  "*.log" in the Directory
# Find. -name "*.log"  -print

Find files that start with an uppercase letter in the directory
# Find/-name "[a-z]*"-print

Find a file that begins with a lowercase letter and ends with a number
# Find/  

　　

(2) File properties options

-perm xxx

Find file permissions of 755 files, can and-find /-perm  755 -print

Find a file the owner is root, the group is also root files (this alone is meaningless, this is a combination of some restrictions)
# Find/-user Root-group Root-print   

And of course there are files that have been deleted by both the owner and the group
# Find. -nouser-nogroup-print

(3) File Time Properties

# Find files accessed within the last 48 hours $    Find/-atime  -2# finds files that have been modified in the last 24  hours $Find /-mtime-1

(4) Ignore a directory

Use the option-prune to ignore the directory. When using the-prune option, be careful not to use with-depth,-prune will be ignored.

#  Ignore the Hello directory under the test directory  $find test  "test/hello"

Description: Find [-path] [expression]

After the path list is an expression

Find test  -path "Test/hello"-prune-o-print
-A and-O are short-circuit evaluation in the shell, with && | | The results are similar.
-path "Test/hello" is true, then the evaluation-prune, then the logic is true, the subsequent-print does not need to execute, otherwise the evaluation-print (using the short-circuit characteristics of-O)
The shell process can be understood as follows:

If-path "Test/hello" Then-pruneelse-print

Ignore operations for multiple directories:

Find  Test  \ (-path test/test4-o-path test/test3 \)  -prune-  o  

Add an escape "\"

Find a certain file,-name and other options after-O

Command:

Find " *.log " -print

(5) Combined use: Add command after Operation find Pathname-option [-print] [-exec-ok command] {} \;

#查看当前目录下的所有普通文件并通过ls-L to show details $ find. -type f-exec ls-l {} \; #还可以再加一些条件, combined using the Find logs  -type f-mtime +5-exec-ok rm-rf {} #删除五日以前有更改的文件  This command is in operation. Very useful, when deleting some log files.

* There is a good application scenario: Find finds files and then grep to see if there are any fields in the file that we need

Look for *.h in #在/tmp, and look for the "TEST" field in these files $ find/tmp-name *.h | Xargs-n50 grep test$ Find/   tmp   -name "*.h"   -exec grep "TEST"   {}   \;-print# copy the found file to the specified place $ find/tmp  -name test-exec cp ' {} '/test '; ' Special files can be used with Cpio's $ find Dir-name filename-print | CPIO-PDV Newdir  (temporarily not later cpio usage, first recorded) #可以使用管道来处理find查找出来的 file list $ find./-name "*.php" | ls-l-full-time 2>/dev/nul l | grep "2016-07-03 22:39" find files changed in 2016-07-03 22:39

　　

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Reference Links:

A Linux command every day find

Examples of Linux find usages

"One day one Linux" find usage detailed notes