Problem:

How to use find command in linux


Solution:



1. Basic find command
# find -name "TestFile"

2. Find Files Using Name and Ignoring Case
# find -iname "TestFile"

3. Limit Search To Specific Directory Level Using mindepth and maxdepth
# find / -maxdepth 3 -name passwd
-maxdepth --> will go 3 directories below -- / 1st; /etc 2nd; /usr/bin 3rd

# find / -mindepth 3 -maxdepth 5 -name passwd
will go 3 depths first and upto 5 -- so will not disply under /; /usr; /usr/bin

4. Executing Commands on the Files Found by the Find Command.
user -exec {} /;
# find -iname "TestFile" -exec md5sum {} \;

5. Inverting the match.
To inver the match use the "-not" switch
# find / -not -iname "TestFile"

6. List inodes of the files
# ls -i1 test*
16187429 test-file-name
16187430 test-file-name

# find -inum 16187430 -exec mv {} new-test-file-name \;
# ls -i1 *test*
16187430 new-test-file-name
16187429 test-file-name

7. Find file based on the File-Permissions
You can :
    * Find files that match exact permission
    * Check whether the given permission matches, irrespective of other permission bits
    * Search by giving octal / symbolic representation

# find . -perm -g=r -type f -exec ls -l {} \;
Will display all files with group permission read. Not files with readonly group permission

# find . -perm g=r -type f -exec ls -l {} \;
Will dispay files with 040 permission. i.e files with group read only permisison

# find . -perm 040 -type f -exec ls -l {} \;
Will dispay files with 040 permission. i.e files with group read only permisison


8. Find all empty files (zero byte file) in your home directory and its subdirectory
# find ~ -empty

Need to check diff
# find . -empty -not -name "test" -- name not equal to test
# find . -not -empty -name ".*"   -- no empty files

9. Finding the Top 5 Big Files
# find /var -type f -exec ls -s {} \; | sort -n -r | head -5

# find /var -type f -size +10M -exec ls -lh {} \;

10. Finding the Top 5 Small Files
# find /var -type f -exec ls -s {} \; | sort -n | head -5
This will most probably list zero byte files or empty files!!!

So to list the smaller files other than the ZERO byte files.
# find /var -not -empty -type f -exec ls -s {} \; | sort -n | head -5

11. Find Files by Size
use the -size switch -- + for greater than; - for lesser than
Find files bigger than the given size
# find / -size +100M

Find files smaller than the given size
# find / -size -100M

Find files that matches the exact given size
# find / -size 100M

Note: – means less than the give size, + means more than the given size, and no symbol means exact given size.

12. Find files based on file types
use -type switch

Find only the socket files.
# find . -type s

Find all directories
# find . -type d

Find only the normal files
# find . -type f

Find all the hidden files
# find . -type f -name ".*"
Find all the hidden directories
# find -type d -name ".*"

13. Creaing aliases:
use the alias command
# alias lslarge="find /var -type f -size +10M -exec ls -lh {} \;"
# lslarge -- will display greater than 10MB files in /var

14. Find Files Based on Access / Modification / Change Time

You can find files based on following three file time attribute.
   1. Modification time of the file. Modification time gets updated when the file content modified.
   2. Access time of the file. Access time gets updated when the file accessed.
   3. Change time of the file. Change time gets updated when the inode data changes.

# min argument treats its argument as minutes. For example, min 60 = 60 minutes (1 hour).
# time argument treats its argument as 24 hours. For example, time 2 = 2*24 hours (2 days)

    * -mmin n File’s data was last modified n minutes ago.
    * -mtime n File’s data was last modified n*24 hours ago.

    * -amin n File was last accessed n minutes ago
    * -atime n File was last accessed n*24 hours ago

    * -cmin n File’s status was last changed n minutes ago. inode change
    * -ctime n File’s status was last changed n*24 hours ago.

14. Find files whose content got updated/Modified within last 1 hour/1Day
# find . -mmin -60  --
# find / -mtime -1 -- finds all the files (under root file system /) that got updated within the last 24 hours (1 day)

15. Find files which got accessed before 1 hour/1Day
# find -amin -60  -- find files in the current directory and sub-directories, which got accessed within last 1 hour (60 minutes)
# find / -atime -1 --

16. Find files which got changed exactly before 1 hour/1day :: inode change
# find . -cmin -60 --
# find / -ctime -1 -- finds all the files (under root file system /) that got changed within the last 24 hours (1 day).

17. Restricting the search only to unhidden files.
# find . -mmin -15 \( ! -regex ".*/\..*" \)
Refer the regex statement

18. Find files modified/accessed/changed after modifying a refrence file
Syntax: # find -newer FILE

# find -newer /etc/passwd   -- Modified after
# find -anewer /etc/hosts     -- Accessed after
# find -cnewer /etc/fstab      -- Changed after

19. Searching Only in the Current Filesystem
use -xdev switch -- Don’t descend directories on other filesystems.

# find / -xdev -name "*.log"
Will search only /, not other mount points mounted under /.

# find / -name "*.log"
This will search all FS starting from /.

20. Using more than one { } in same command
# find -name "*.txt" cp {} {}.bkup \;

21. Redirecting errors to /dev/null
# find -name "*.txt" 2>>/dev/null

22. Substitute space with underscore in the file name.
# find . -type f -iname “*.mp3″ -exec mv “s/ /_/g” {} \;