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Linux find 15 commonly used commands

巴扎黑
Release: 2017-08-10 11:10:47
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[Introduction] In addition to the basic operation of searching for files in a directory structure, you can also use the find command to implement some practical operations to make your command line journey easier. This article will introduce 15 Linux find commands that are very useful for both novices and veterans. First, create a file under your home directory. In addition to basic operations such as searching for files in a directory structure, you can also use the find command to perform some practical operations to make your command line journey easier. .

This article will introduce 15 Linux find commands that are very useful for both novices and veterans.

First, create the following empty file in your home directory to test the following find command example.

01
# vim create_sample_files.sh
##02touch MybashProgram.sh
##03touch mycprogram.c##04
touch MyCProgram.c##05
touch Program.c##06
mkdir backup
##07
##08cd backup
##09
##10touch MybashProgram.sh
##11
touch mycprogram.c
##12touch MyCProgram.c
13touch Program.c
##14##15
# chmod +x create_sample_files.sh##16
##17# ./create_sample_files.sh
##18
##19# ls -R
20.:
twenty onebackup MybashProgram.sh MyCProgram.c
twenty twocreate_sample_files.sh mycprogram.c Program.c
twenty three
twenty four./backup:
##25 MybashProgram.sh mycprogram.c MyCProgram.c Program.c
1. Find files by file nameThis is a basic usage of the find command. The following example shows how to use MyCProgram.c as the search name to find files in the current directory and its subdirectories. 1
# find -name "MyCProgram.c"2
./backup/MyCProgram.c

##3./MyCProgram.c
2. Find files by file name, ignoring case This is a basic usage of the find command. The following example shows how to find files in the current directory and its subdirectories using MyCProgram.c as the search name, ignoring case. 1# find -iname "MyCProgram.c"
2./mycprogram.c

##3
./backup/mycprogram.c
##4./backup/MyCProgram.c
##5./MyCProgram.c3. Use mindepth and maxdepth to limit the depth of the search for the specified directory Find the passwd file in the root directory and its subdirectories.
1 # find / -name passwd
2 ./usr/share/doc/nss_ldap-253/pam.d/passwd
3 ./usr/bin/passwd
##4./etc/pam.d/passwd
##5Look for passwd in the root directory and one sub-directory one level deep. (For example, root — level 1, and one sub-directory — level 2)
./etc/passwd

1
# find -maxdepth 2 -name passwd
2Look for the passwd file in the root directory and its subdirectories up to two levels deep. (For example, root — level 1, and two sub-directories — level 2 and 3)
./etc/passwd

1
# find / -maxdepth 3 -name passwd
2
./usr/bin/passwd
##3./etc/pam.d/passwd
##4./etc/passwdLook for the passwd file between the second-level subdirectory and the fourth-level subdirectory.

1# find -mindepth 3 -maxdepth 5 -name passwd
2./usr/bin/passwd##3
./etc/pam.d/passwdThe following example shows the find command to count all case-insensitive files named "MyCProgram .c" file's MD5 verification sum. {} will be replaced by the current file name.
4. Execute the command on the file found by the find command

1

find -iname "MyCProgram.c" -exec md5sum {} \;2
d41d8cd98f00b204e9800998ecf8427e ./mycprogram.c##3
d41d8cd98f00b204e9800998ecf8427e ./backup/mycprogram.c##4d41d8cd98f00b204e9800998ecf8427e ./backup/MyCProgram.c
d41d8cd98f00b204e9800998ecf8427e ./MyCProgram.c
##5
5. On the contrary, matching displays all files or directories whose names are not MyCProgram.c. Since maxdepth is 1, only files and directories in the current directory will be displayed.
1

find -maxdepth 1 -not -iname "MyCProgram.c"

.
2
##3./MybashProgram.sh
##4 ./create_sample_files.sh
##5./backup
##66. Use inode number to find files
./Program.c
Any file has a unique inode number, through which we can distinguish files. Create two files with similar names, for example one with trailing spaces and one without. touch "test-file-name"
1

2
##3# touch "test-file-name "
##4[Note: There is a space at the end]##5
##6
# ls -1 test*##7test-file-name
8test-file-name
1
The output of ls cannot tell which file has a trailing space. Using the option -i, you can see the inode number of the file, so you can distinguish the two files.
ls -i1 test*2

16187429 test-file-name

16187430 test-file-name
##3

You can specify the inode number in the find command as shown below. Here, the find command renames a file with the inode number.

1 find -inum 16187430 -exec mv {} new-test-file-name \;
2
##3# ls -i1 *test*
##4
16187430 new-test-file-name
##516187429 test-file-name#You can use this technique when you want to do something with a poorly named file like the one above. For example, the file named file?.txt has a special character in its name. If you want to execute "rm file?.txt", all three files shown below will be deleted. So, follow the steps below to delete the "file?.txt" file.


1ls
2file1.txt file2.txt file?.txtFind the inode number of each file.

1ls -i1
2804178 file1.txt
##3804179 file2.txt##4
804180 file?.txt
is as follows: Use the inode number to delete those file names with special symbols.

1

find -inum 804180 -exec rm {} \;2
##3
# ls##4file1.txt file2.txt
[Note: The file with name "file?.txt" is now removed]
##5
7. Find files based on file permissionsThe following operations are reasonable:Find files with specified permissions

Ignore other permission bits and check if they match the specified permissions

  • Search based on the permissions expressed in the given octal/symbol expression

  • In this example, assume that the directory contains the following files. Note that these files have different permissions.

  • 1
ls -l

total 0
2
##3-rwxrwxrwx 1 root root 0 2009-02-19 20:31 all_for_all
##4 -rw-r--r-- 1 root root 0 2009-02-19 20:30 everybody_read
##5---------- 1 root root 0 2009-02-19 20:31 no_for_all
##6
-rw------- 1 root root 0 2009-02-19 20:29 ordinary_file
##7-rw-r----- 1 root root 0 2009-02-19 20:27 others_can_also_read
8----r----- 1 root root 0 2009-02-19 20:27 others_can_only_readFind the file with group read permissions. Use the following command to find files in the current directory that have read permissions for users in the same group, ignoring other permissions on the file.
1find . -perm -g=r -type f -exec ls -l {} \;

2-rw-r--r-- 1 root root 0 2009-02-19 20:30 ./everybody_read
##3-rwxrwxrwx 1 root root 0 2009-02-19 20:31 ./all_for_all##4
----r----- 1 root root 0 2009-02-19 20:27 ./others_can_only_read##5
-rw-r----- 1 root root 0 2009-02-19 20:27 ./others_can_also_readFind files that have read-only permissions for group users.
1find . -perm g=r -type f -exec ls -l {} \;
2

----r----- 1 root root 0 2009-02-19 20:27 ./others_can_only_read

Find files with read-only permissions for group users (using octal permission form).

1 find . -perm 040 -type f -exec ls -l {} \;
2 ----r----- 1 root root 0 2009-02-19 20:27 ./others_can_only_read

8. Find all empty files (0-byte files) in the home directory and subdirectories

Most of the output files of the following commands are locked file boxes Place hoders created by other programs

1 find ~ -empty

Only list empty files in your home directory.

1 find . -maxdepth 1 -empty


# Only list non-hidden empty files in the current directory.

1 find . -maxdepth 1 -empty -not -name ".*"

9. Find the 5 largest files

The following command lists the 5 largest files in the current directory and subdirectories. This can take a while, depending on the number of files the command needs to process.

1 find . -type f -exec ls -s {} \; | sort -n -r | head -5

10. Find the 5 smallest files

The method is similar to the method of finding the 5 largest files, the only difference is that the sort order is descending order.

1 find . -type f -exec ls -s {} \; | sort -n | head -5

In the above command, it is very likely that what you see is just an empty file (0-byte file). So, you can use the following command to list the smallest files instead of 0 byte files.

1 find . -not -empty -type f -exec ls -s {} \; | sort -n | head -5

11. Use -type to find files of the specified file type

Only search for socket files

1 find . -type s

Find all directories

1 find . -type d

Find all general files

1 find . -type f

Find all hidden files

1 find . -type f -name ".*"

Find all hidden directories

1 find -type d -name ".*"

12. Find files by comparing modification times with other files

Display files that were modified after the specified file. The find command below will display all files created and modified after ordinary_file.

01 ls -lrt
##02total 0
##03
-rw-r----- 1 root root 0 2009-02-19 20:27 others_can_also_read
##04----r----- 1 root root 0 2009-02-19 20:27 others_can_only_read
##05-rw------- 1 root root 0 2009-02-19 20:29 ordinary_file##06
-rw-r--r-- 1 root root 0 2009-02-19 20:30 everybody_read##07
-rwxrwxrwx 1 root root 0 2009-02-19 20:31 all_for_all##08---------- 1 root root 0 2009-02-19 20:31 no_for_all
##09
##10# find -newer ordinary_file
##11 .
##12./everybody_read
13./all_for_all
##1413. Find files by file size
./no_for_all
Use the -size option to find files by file size. Find files larger than the specified file1
find ~ -size +100M

Find files smaller than the specified file

1 find ~ -size -100M

Find files matching the given size

1 find ~ -size 100M

Note: – means smaller than the given size, + means larger than the given size. No symbol indicates exactly the same size as a given size.

14. Give aliases to commonly used find operations

If you find something useful, you can give it an alias. And execute it anywhere you want.

Commonly used to delete the a.out file.

1 alias rmao="find . -iname a.out -exec rm {} \;"
2 #rmao

Delete the core file generated by the c program.

1 alias rmc="find . -iname core -exec rm {} \;"
2 #rmc

15. Use the find command to delete large packaged files

The following command deletes *.zip files larger than 100M.

1 find / -type f -name *.zip -size +100M -exec rm -i {} \;"

Use the alias rm100m to delete all *.tar files of Heavy Rain 100M. Using the same idea, you can create a category name of rm1g, rm2g, and rm5g to delete all files larger than 1G, 2G, and 5G.

1 alias rm100m="find / -type f -name *.tar -size +100M -exec rm -i {} \;"
2 # alias rm1g="find / -type f -name *.tar -size +1G -exec rm -i {} \;"
##3# alias rm2g="find / -type f -name *.tar -size +2G -exec rm -i {} \;"
##4
# alias rm5g="find / -type f -name *.tar -size +5G -exec rm -i {} \;"
##5
##6# rm100m##7
#rm1g8
# rm2g9
# rm5g
Find command example (Part 2)

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