Introduction to the find command in Linux

preface

The Find command on the Linux system has powerful search capabilities and can traverse the entire file system. So the find command is resource-intensive and sometimes even time-consuming, so it is recommended that it be executed in the background.

The Find command format is as follows:

find pathname -options [-print -exec -ok …]

A simple format to remember:

find <指定目录> <指定条件> <指定动作>

Action parameters

1, -exec command name {} \;

Execute the unix command given to the qualified file without asking the user if he needs to execute the command. {} indicates that the parameter of the command is the file found, and the end of the command must be "\;" End, "{}" and "\;" There must be one space between them.

2, -ok command name {} \;

Execute the Linux command given to a qualified file, and unlike exec, it asks the user if they need to execute the command.

3, - ls

List all files found in detail.

4. -fprintf file name

Writes the found file name to the specified file.

5, - print

Displays the found file name on the standard output device.

6, - printf

The format can be used in a book about the C language.

Command options

1, - name

Look for files by filename.

2, - perm

Find files by file permissions.

3, - prune

Use this 1 option to keep the find command from looking in the currently specified directory, and -prune will be ignored by the find command if the -depth option is used at the same time.

4, - user

Find the file by file owner.

5, - group

Find files by the group they belong to.

6, - nogroup

Find a file that does not have a valid group to which it belongs, i.e. the group to which it belongs does not exist in /etc/groups.

7, - nouser

Find a file with no valid owner, that is, the owner of the file does not exist in /etc/passwd.

8. -newer file1! file2

Find files that are newer than file file1 but older than file file2.

9, - regex pattern

The file name matches the regular expression pattern. This is a match for the entire path, not a search file. For example, to match a file named './fubar3', you can use the regular expression '.bar.' or '.* b.3 ', but not 'b.*r3'.

10 - type

Find a file of type 1, such as:

b - block device file. d - directory. c - character device file. p - pipeline file. l - symbolic link file. f - general file

10. -size n: [c]

Find a file with a file length of n block, with c indicating the file length in bytes.

11, - depth

When looking for a file, first look for the file in the current directory and then look in its subdirectory.

12, - fstype

Look for files located on a type 1 file system. These file system types can usually be found in the configuration file /etc/fstab, which contains information about the file system in the system.

13, - mount

Do not cross the file system mount point when searching for files.

14, - follow

If the find command encounters a symbolic link file, it tracks to the file to which the link points.

15, - cpio

Use the cpio command for matching files to back them up to a tape device.

16. Time control

-mtime -n +n

Find the file by the time it has changed, -n means that the file has changed within days of n, + n means that the file has changed within days of n. The find command also has -atime and -ctime options, but they are both similar to -mtime option 1, looking for files by time node, but with some differences:

-amin n finds the last file on the system that N accessed in minutes -atime n finds the last n* 24-hour access file in the system -cmin n finds the last N minute in the system where the file state was changed -ctime n finds the last file on the system that n* changed file status 24 hours a day -mmin n finds the last N minute file data changed in the system -mtime n finds the last file in the system that n* changed file data 24 hours a day

Logic control

Logic and

expr1 -a expr2

expr1 -and expr2

Find files that satisfy both the criteria expr1 and expr2, for example, find files that belong to neither the master nor the group in the whole system:

find / -nogroup  � a  � nouser

Logic or

expr1 -o expr2

expr1 -or expr2

Find a file that meets the criteria expr1 or expr2, for example, find a file in the tmp directory that ends in ".sh "or ends in".log ":

find /tmp -name  " .sh "  -o -name  " .log " 

Logic is not

-not expr

Find files that do not meet the expr criteria, such as files belonging to a user other than root in the /tmp directory:

find /tmp -not -user root -exec ls -l {} \;

Some typical applications

Recursively modify all directory permissions under the directory (only modify the directory, not the file)

Three ways:

1 ,  find path -type d -exec chmod 744{} \; ( There is a semicolon at the end of this sentence )

2 ,  find path -type d | xargs chmod 744

3 ,  chmod 755 `find -type d`

Recursively modify the permissions of all normal files in the directory (only modify files, do not modify the directory)

Three ways:

1 ,  find path -type f -exec chmod 644 {} \; 
2 ,  find path -type f | xargs chmod 644 
3 ,  chmod 755 `find -type f` 

Recursively deletes all files of the execution type

For example, recursively delete the.exe normal file in the current directory:

expr1 -and expr2

0

In addition to -exec, you can also use pipes, such as recursively deleting.deb files in the current directory:

expr1 -and expr2

1

Count the number of lines of code

expr1 -and expr2

2

This command may fail on other platforms, so you can use grep to filter files:

wc -l `find $path | grep ".*\.\(py\|html\|js\|css\)$"`

conclusion

The above is the whole content of this article, I hope the content of this article to your study or work can bring 1 definite help, if you have questions you can leave a message to communicate.