Linux find command

The Linux find command is a very useful and handy command to search for files from the command line. It can be used to find files based on various search criterias like permissions, user ownership, modification date/time, size etc. In this post we shall learn to use the find command along with various options that it supports.

The find command is available on most linux distros by default so you do not have to install any package. The find command is an essential one to learn, if you want to get super productive with the command line on linux.

The basic syntax of the find command looks like this

$ find location comparison-criteria search-term

1. List all files in current and sub directories

This command lists out all the files in the current directory as well as the subdirectories in the current directory.

$ find . ./abc.txt ./subdir ./subdir/how.php ./cool.php

The command is same as the following

$ find . $ find . -print

2. Search specific directory or path

The following command will look for files in the test directory in the current directory. Lists out all files by default.

$ find ./test ./test ./test/abc.txt ./test/subdir ./test/subdir/how.php ./test/cool.php

The following command searches for files by their name.

$ find ./test -name "abc.txt" ./test/abc.txt

We can also use wildcards

$ find ./test -name "*.php" ./test/subdir/how.php ./test/cool.php

Note that all sub directories are searched recursively. So this is a very powerful way to find all files of a given extension.

Trying to search the "/" directory which is the root, would search the entire file system including mounted devices and network storage devices. So be careful. Of course you can press Ctrl + c anytime to stop the command.

When specifying the directory ("./test" in this example), its fine to omit the trailing slash. However, if the directory is actually a symlink to some other location then you MUST specify the trailing slash for it to work properly (find ./test/ ...)

Ignore the case

It is often useful to ignore the case when searching for file names. To ignore the case, just use the "iname" option instead of the "name" option.

$ find ./test -iname "*.Php" ./test/subdir/how.php ./test/cool.php

Its always better to wrap the search term (name parameter) in double or single quotes. Not doing so will seem to work sometimes and give strange results at other times.

3. Limit depth of directory traversal

The find command by default travels down the entire directory tree recursively, which is time and resource consuming. However the depth of directory travesal can be specified. For example we don't want to go more than 2 or 3 levels down in the sub directories. This is done using the maxdepth option.

$ find ./test -maxdepth 2 -name "*.php" ./test/subdir/how.php ./test/cool.php $ find ./test -maxdepth 1 -name *.php ./test/cool.php

The second example uses maxdepth of 1, which means it will not go lower than 1 level deep, either only in the current directory.

This is very useful when we want to do a limited search only in the current directory or max 1 level deep sub directories and not the entire directory tree which would take more time.

Just like maxdepth there is an option called mindepth which does what the name suggests, that is, it will go atleast N level deep before searching for the files.

4. Invert match

It is also possible to search for files that do no match a given name or pattern. This is helpful when we know which files to exclude from the search.

$ find ./test -not -name "*.php" ./test ./test/abc.txt ./test/subdir

So in the above example we found all files that do not have the extension of php, either non-php files. The find command also supports the exclamation mark inplace of not.

find ./test ! -name "*.php"

5. Combine multiple search criterias

It is possible to use multiple criterias when specifying name and inverting. For example

$ find ./test -name 'abc*' ! -name '*.php' ./test/abc.txt ./test/abc

The above find command looks for files that begin with abc in their names and do not have a php extension. This is an example of how powerful search expressions can be build with the find command.

OR operator

When using multiple name criterias, the find command would combine them with AND operator, which means that only those files which satisfy all criterias will be matched. However if we need to perform an OR based matching then the find command has the "o" switch.

$ find -name '*.php' -o -name '*.txt' ./abc.txt ./subdir/how.php ./abc.php ./cool.php

The above command search for files ending in either the php extension or the txt extension.

6. Search only files or only directories

Sometimes we want to find only files or only directories with a given name. Find can do this easily as well.

$ find ./test -name abc* ./test/abc.txt ./test/abc Only files $ find ./test -type f -name "abc*" ./test/abc.txt Only directories $ find ./test -type d -name "abc*" ./test/abc

Quite useful and handy!

7. Search multiple directories together

So lets say you want to search inside 2 separate directories. Again, the command is very simple

$ find ./test ./dir2 -type f -name "abc*" ./test/abc.txt ./dir2/abcdefg.txt

Check, that it listed files from 2 separate directories.

8. Find hidden files

Hidden files on linux begin with a period. So its easy to mention that in the name criteria and list all hidden files.

$ find ~ -type f -name ".*"

9. Find files with certain permissions

The find command can be used to find files with a specific permission using the "perm" option. The following command searches for files with the permission 0664

$ find . -type f -perm 0664 ./abc.txt ./subdir/how.php ./abc.php ./cool.php

This can be useful to find files with wrong permissions which can lead to security issues. Inversion can also be applied to permission checking.

$ find . -type f ! -perm 0777 ./abc.txt ./subdir/how.php ./abc.php ./cool.php

10. Find files with sgid/suid bits set

The "perm" option of find command accepts the same mode string like chmod. The following command finds all files with permission 644 and sgid bit set.

# find / -perm 2644

Similarly use 1664 for sticky bit. The perm option also supports using an alternative syntax instead of octal numbers.

$ find / -maxdepth 2 -perm /u=s 2>/dev/null /bin/mount /bin/su /bin/ping6 /bin/fusermount /bin/ping /bin/umount /sbin/mount.ecryptfs_private

Note that the "2>/dev/null" removes those entries that have an error of "Permission Denied"

11. Find readonly files

Find all Read Only files.

$ find /etc -maxdepth 1 -perm /u=r /etc /etc/thunderbird /etc/brltty /etc/dkms /etc/phpmyadmin ... output truncated ...

12. Find executable files

The following command will find executable files

$ find /bin -maxdepth 2 -perm /a=x /bin /bin/preseed_command /bin/mount /bin/zfgrep /bin/tempfile ... output truncated ...

13. Find files owned to particular user

To find all or single file called tecmint.txt under /root directory of owner root.

$ find . -user bob . ./abc.txt ./abc ./subdir ./subdir/how.php ./abc.php

We could also specify the name of the file or any name related criteria along with user criteria

$ find . -user bob -name '*.php'

Its very easy to see, how we can build up criteria after criteria to narrow down our search for matching files.

14. Search files belonging to group

Find all files that belong to a particular group.

# find /var/www -group developer

Did you know you could search your home directory by using the ~ symbol ?

$ find ~ -name "hidden.php"

Easy!!

Search file and directories based on modification date and time

Another great search criteria that the find command supports is modification and accessed date/times. This is very handy when we want to find out which files were modified as a certain time or date range. Lets take a few examples

15. Find files modified N days back

To find all the files which are modified 50 days back.

# find / -mtime 50

16. Find files accessed in last N days

Find all files that were accessed in the last 50 days.

# find / -atime 50

17. Find files modified in a range of days

Find all files that were modified between 50 to 100 days ago.

# find / -mtime +50 –mtime -100

18. Find files changed in last N minutes.

Find files modified within the last 1 hour.

$ find /home/bob -cmin -60

19. Files modified in last hour

To find all the files which are modified in last 1 hour.

# find / -mmin -60

20. Find Accessed Files in Last 1 Hour

To find all the files which are accessed in last 1 hour.

# find / -amin -60

21. Find files of given size

Search files and directories based on size. To find all 50MB files, use.

# find / -size 50M

22. Find files in a size range

To find all the files which are greater than 50MB and less than 100MB.

$ find / -size +50M -size -100M

23. Find largest and smallest files

The find command when used in combination with the ls and sort command can be used to list out the largest files.

The following command will display the 5 largest file in the current directory and its subdirectory. This may take a while to execute depending on the total number of files the command has to process.

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

Similary when sorted in ascending order, it would show the smallest files first

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

24. Find empty files and directories

The following command uses the "empty" option of the find command, which finds all files that are empty.

# find /tmp -type f -empty

To file all empty directories use the type "d".

$ find ~/ -type d -empty

Really very simple and easy

Some advanced operations

The find command not only finds files based on a certain criteria, it can also act upon those files using any linux command. For example, we might want to delete some files.

Here are some quick examples

25. List out the found files

Lets say we found files using find command, and now want to list them out as the ls command would have done. This is very easy.

$ find . -exec ls -ld {} \; drwxrwxr-x 4 enlightened enlightened 4096 Aug 11 19:01 . -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:25 ./abc.txt drwxrwxr-x 2 enlightened enlightened 4096 Aug 11 16:48 ./abc drwxrwxr-x 2 enlightened enlightened 4096 Aug 11 16:26 ./subdir -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:26 ./subdir/how.php -rw-rw-r-- 1 enlightened enlightened 29 Aug 11 19:13 ./abc.php -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:25 ./cool.php

26. Delete all matching files or directories

The following command will remove all text files in the tmp directory.

$ find /tmp -type f -name "*.txt" -exec rm -f {} \;

The same operating can be carried out with directories, just put type d, instead of type f.

Lets take another example where we want to delete files larger than 100MB

$ find /home/bob/dir -type f -name *.log -size +10M -exec rm -f {} \;

Summary

So that was a quick tutorial on the linux find command. The find command is one of the most essential commands on the linux terminal, that enables searching of files very easy. Its a must of all system administrators. So learn it up. Have any questions ? Leave a comment below.