These are 10 useful uses of the command find in Linux, they are not the most useful, just some useful for me, I will use $HOME as the path for every example but you may use any other.
1. Find empty directories
find $HOME -depth -type d -empty
This will find empty directories in your home directory.
2. Find empty files
find $HOME -depth -type f -empty
This will find empty common files in your home directory.
3. Find a file with a specific name
find $HOME -name [name_of_file]
This will find files with a given name in any child directory of your home.
4. Find a file with a specific extension
find $HOME -name "*.[given_extension]"
This find files wit the given extension all along your home, an example to find jpg files is:
find $HOME -name '*.jpg'
5. Find files with specific permissions
find $HOME -perm [permission bits]
This will find files with the given permission bits in your home, as an example we can look for .txt files that can have 644 bits on.
find $HOME -name '*.txt' -perm 644
6. Find files with some given permissions and no matter the rest
find $HOME -perm -[permision_bits]
This will find files in your home that have match with the given permissions but that can also have some others, as an example:
find $HOME -name '*.txt' -perm -644
This will find the files with 644 but also some with 664 or 777 or anything "greater" than 644.
Output comparison
Let's see some output comparison for this to be better understood.
find $HOME -name '*.txt' -perm 644 -exec ls -l {} \;
-rw-r--r-- 1 root root 181 2007-10-09 23:27 /home/dejavu/lmsensors.txt
-rw-r--r-- 1 dejavu dejavu 2757 2007-08-29 23:52 /home/dejavu/mv.txt
-rw-r--r-- 1 dejavu dejavu 77431 2007-09-05 23:11 /home/dejavu/curl.txt
find $HOME -name '*.txt' -perm -644 -exec ls -l {} \;
-rw-r--r-- 1 root root 181 2007-10-09 23:27 /home/dejavu/lmsensors.txt
-rw-r--r-- 1 dejavu dejavu 2757 2007-08-29 23:52 /home/dejavu/mv.txt
-rw-r--r-- 1 dejavu dejavu 77431 2007-09-05 23:11 /home/dejavu/curl.txt
-rw-rw-r-- 1 dejavu dejavu 464 2007-09-06 01:23 /home/dejavu/post.txt
As you may see in the first example we do not have the file post as it has 664 permissions, so do not exactly match 644, but on the second output, it is listed as it has "greater" permissions than 644
.
7. Find files of given sizes
find -size n[cwbkMG]
This will output the files of a given block size, as an example we can see:
find $HOME -name '*.txt' -size 4k -exec ls -l {} \;
And the output is:
-rw-r--r-- 1 dejavu dejavu 3707 2007-07-25 15:48
/home/dejavu/drupal/public_html/sites/all/modules/akismet/README.txt
-rw-r--r-- 1 dejavu dejavu 4043 2007-01-22 15:44 /home/dejavu/Desktop/front/README.txt
-rw-r--r-- 1 dejavu dejavu 3112 2007-09-23 15:39
/home/dejavu/Desktop/borrar/upgrading-drupal/public_html/sites/all/modules/adsense/README.txt
-rw-r--r-- 1 dejavu dejavu 3707 2007-09-23 15:39
/home/dejavu/Desktop/borrar/upgrading-drupal/public_html/sites/all/modules/akismet/README.txt
-rw-r--r-- 1 dejavu dejavu 3616 2007-09-23 15:39
/home/dejavu/Desktop/borrar/centos-asterisk/how-to-install.txt
Now let's see this other:
find $HOME -name '*.txt' -size 5k -exec ls -l {} \;
And the output is:
-rw-r--r-- 1 dejavu dejavu 4496 2007-09-23 15:39
/home/dejavu/Desktop/borrar/upgrading-drupal/public_html/sites/all/modules/captcha/captcha_api.txt
Now if you divide each file size by 1024 (1k) you will see that the first output is always lower than 4096 (4k) and upper 3072 (3k), on the second output you have it between 4096 (4k) and 5120 (5k)
8. Find files with a give name and any extension
find -name '[given_name].*'
This will output the files of any given name but with any extension
9. Find files modified in the latest blocks of 24 hours
find -mtime n
Where n is:
0 for the last 24 hours
1 for the last 48 hours
2 for the last 72 hours
and so on.
10. Find files that was accessed in the latests blocks of 24 hours
find -atime n
Where n is:
0 for the last 24 hours
1 for the last 48 hours
2 for the last 72 hours
and so on.
I have been using in the examples the -exec parameter, this is used to execute any action over the find files, I was listing them but you may delete them or move them or copy them anything you want.
