15 practical Linux find command examples

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

02 touch MybashProgram.sh

03 touch mycprogram.c

04 touch MyCProgram.c

05 touch Program.c

06

07 mkdir backup

08 cd backup

09

10 touch MybashProgram.sh

11 touch mycprogram.c

12 touch MyCProgram.c

13 touch Program.c

14

15 # chmod +x create_sample_files.sh

16

17 # ./create_sample_files.sh

18

19 # ls -R

20 .:

21 backup MybashProgram.sh MyCProgram.c​

22 ​ create_sample_files.sh ​ mycprogram.c ​ ​ Program.c ​

23 ​

24 ./ backup:

25 MybashProgram.sh mycprogram.c MyCProgram.c Program.c

1. Find files by file name

This 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. Use the file name to find the file, ignoring case

This is the find command A basic usage. 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.c

3. 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

5 ./etc/passwd

Find passwd in the root directory and its 1-level-deep subdirectory. (For example, root — level 1, and one sub-directory — level 2)

1 # find -maxdepth 2 -name passwd

2 ./etc/passwd

Search for passwd files 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)

/1# Find/-maxDepth 3 -Name Passwd

2 ./usr/bin/passwd

3 ./etc/pam.d/passwd

4 ./etc/passwd

Look for the passwd file among the fourth-level subdirectories.

1 # find -mindepth 3 -maxdepth 5 -name passwd

2 ./usr/bin/passwd

3 ./etc/pam.d/passwd

4. Execute the command on the file found by the find command

The following example shows the find command to calculate the MD5 verified sum of all case-insensitive files named "MyCProgram.c". {} will be replaced by the current file name.

1 find -iname "MyCProgram.c" -exec md5sum {} ;

2 d41d8cd98f00b204e9800998ecf8427e ./mycprogram.c

3 d41d8cd98f 00b204e9800998ecf8427e ./backup/mycprogram.c

4 d41d8cd98f00b204e9800998ecf8427e ./backup/MyCProgram.c

5 d41d8cd98f00b204e9800998ecf8427e ./MyCProgram.c

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

6 ./Program.c

6. Find files using inode numbers

Every file has one A unique inode number by which we can distinguish files. Create two files with similar names, for example one with trailing spaces and one without.

1 touch "test-file-name"

2

3 # touch "test-file-name"

4 [Note: There is a space at the end]

5

6 # ls -1 test*

7 test-file-name

8 test-file-name

From the output of ls, we cannot distinguish 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.

1 ls -i1 test*

2 16187429 test-file-name

3 16187430 test-file-name

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

5 16187429 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.

1 ls

2 file1.txt file2.txt file?.txt

Find the inode number of each file.

1 ls -i1

2 804178 file1.txt

3 804179 file2.txt

4 804180 file?.txt As shown below: Use the inode number to remove those file names with special symbols.

1 find -inum 804180 -exec rm {} ;

2

3 # ls

4 file1.txt file2.txt

5 [Note: The filewith name "file?.txt" is now removed]

7. Find files based on file permissions

The following operations are reasonable:

Find files with specified permissions

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

Expressed based on the given octal/symbol Permission Search

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

1 ls -l

2 total 0

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_read

Find files 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.

1 find . -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_read

Find files with read-only permissions for group users.

1 find . -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 that have 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 command are locked files and 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. The method of finding the 5 smallest files

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

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

In the above command, it is likely that you only see empty files (0-byte files). 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 find 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 time with other files

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

01 ls -lrt

02 total 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

14 ./no_for_all

13. Find files by file size

Use the -size option to find files by their size.

Find files larger than the specified file

1 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 a.out files.

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 package 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 heavy rain 100M *.tar files. Use the same idea to create rm1g, rm2g , a category name of rm5g to delete all files larger than 1G, 2G, 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 # rm1g

8 # rm2g

9 # rm5g

Find command example (Part 2)

For more 15 practical Linux find command examples and related articles, please pay attention to the PHP Chinese website!