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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 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. | ||
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The basic syntax of the find command looks like this | The basic syntax of the find command looks like this | ||
| − | $ find location comparison-criteria search-term | + | $ find location comparison-criteria search-term |
| + | |||
| + | =Basic examples= | ||
| − | + | ==1. List all files in current and sub directories== | |
| − | 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. | This command lists out all the files in the current directory as well as the subdirectories in the current directory. | ||
| − | $ find | + | $ find |
| − | . | + | . |
| − | ./abc.txt | + | ./abc.txt |
| − | ./subdir | + | ./subdir |
| − | ./subdir/how.php | + | ./subdir/how.php |
| − | ./cool.php | + | ./cool.php |
The command is same as the following | The command is same as the following | ||
| − | $ find . | + | $ find . |
| − | $ find . -print | + | $ find . -print |
| − | 2. Search specific directory or path | + | ==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. | The following command will look for files in the test directory in the current directory. Lists out all files by default. | ||
| − | $ find ./test | + | $ find ./test |
| − | ./test | + | ./test |
| − | ./test/abc.txt | + | ./test/abc.txt |
| − | ./test/subdir | + | ./test/subdir |
| − | ./test/subdir/how.php | + | ./test/subdir/how.php |
| − | ./test/cool.php | + | ./test/cool.php |
The following command searches for files by their name. | The following command searches for files by their name. | ||
| − | $ find ./test -name "abc.txt" | + | $ find ./test -name "abc.txt" |
| − | ./test/abc.txt | + | ./test/abc.txt |
We can also use wildcards | We can also use wildcards | ||
| − | $ find ./test -name "*.php" | + | $ find ./test -name "*.php" |
| − | ./test/subdir/how.php | + | ./test/subdir/how.php |
| − | ./test/cool.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. | Note that all sub directories are searched recursively. So this is a very powerful way to find all files of a given extension. | ||
| Line 61: | Line 56: | ||
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/ ...) | 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 | + | ===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. | 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" | + | $ find ./test -iname "*.Php" |
| − | ./test/subdir/how.php | + | ./test/subdir/how.php |
| − | ./test/cool.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. | 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 | + | ==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. | 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" | + | $ find ./test -maxdepth 2 -name "*.php" |
| − | ./test/subdir/how.php | + | ./test/subdir/how.php |
| − | ./test/cool.php | + | ./test/cool.php |
| − | $ find ./test -maxdepth 1 -name *.php | + | $ find ./test -maxdepth 1 -name *.php |
| − | ./test/cool.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. | The second example uses maxdepth of 1, which means it will not go lower than 1 level deep, either only in the current directory. | ||
| Line 87: | Line 82: | ||
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. | 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 | + | |
| + | ==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. | 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" | + | $ find ./test -not -name "*.php" |
| − | ./test | + | ./test |
| − | ./test/abc.txt | + | ./test/abc.txt |
| − | ./test/subdir | + | ./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. | 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" | + | find ./test ! -name "*.php" |
| − | 5. Combine multiple search criterias | + | ==5. Combine multiple search criterias== |
It is possible to use multiple criterias when specifying name and inverting. For example | It is possible to use multiple criterias when specifying name and inverting. For example | ||
| − | $ find ./test -name 'abc*' ! -name '*.php' | + | $ find ./test -name 'abc*' ! -name '*.php' |
| − | ./test/abc.txt | + | ./test/abc.txt |
| − | ./test/abc | + | ./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. | 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 | + | ===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. | 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' | + | $ find -name '*.php' -o -name '*.txt' |
| − | ./abc.txt | + | ./abc.txt |
| − | ./subdir/how.php | + | ./subdir/how.php |
| − | ./abc.php | + | ./abc.php |
| − | ./cool.php | + | ./cool.php |
The above command search for files ending in either the php extension or the txt extension. | The above command search for files ending in either the php extension or the txt extension. | ||
| − | 6. Search only files or only directories | + | |
| + | ==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. | 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* | + | $ find ./test -name abc* |
| − | ./test/abc.txt | + | ./test/abc.txt |
| − | ./test/abc | + | ./test/abc |
Only files | Only files | ||
| − | $ find ./test -type f -name "abc*" | + | $ find ./test -type f -name "abc*" |
| − | ./test/abc.txt | + | ./test/abc.txt |
Only directories | Only directories | ||
| − | $ find ./test -type d -name "abc*" | + | $ find ./test -type d -name "abc*" |
| − | ./test/abc | + | ./test/abc |
Quite useful and handy! | Quite useful and handy! | ||
| − | 7. Search multiple directories together | + | |
| + | ==7. Search multiple directories together== | ||
So lets say you want to search inside 2 separate directories. Again, the command is very simple | So lets say you want to search inside 2 separate directories. Again, the command is very simple | ||
| − | $ find ./test ./dir2 -type f -name "abc*" | + | $ find ./test ./dir2 -type f -name "abc*" |
| − | ./test/abc.txt | + | ./test/abc.txt |
| − | ./dir2/abcdefg.txt | + | ./dir2/abcdefg.txt |
Check, that it listed files from 2 separate directories. | Check, that it listed files from 2 separate directories. | ||
| − | 8. Find hidden files | + | |
| + | ==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. | 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 ".*" | + | $ find ~ -type f -name ".*" |
Find files based on permissions | Find files based on permissions | ||
| − | 9. Find files with certain permissions | + | |
| + | ==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 | 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 | + | $ find . -type f -perm 0664 |
| − | ./abc.txt | + | ./abc.txt |
| − | ./subdir/how.php | + | ./subdir/how.php |
| − | ./abc.php | + | ./abc.php |
| − | ./cool.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. | 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 | + | $ find . -type f ! -perm 0777 |
| − | ./abc.txt | + | ./abc.txt |
| − | ./subdir/how.php | + | ./subdir/how.php |
| − | ./abc.php | + | ./abc.php |
| − | ./cool.php | + | ./cool.php |
| − | 10. Find files with sgid/suid bits set | + | ==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. | 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 | + | # find / -perm 2644 |
Similarly use 1664 for sticky bit. The perm option also supports using an alternative syntax instead of octal numbers. | 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 | + | $ find / -maxdepth 2 -perm /u=s 2>/dev/null |
| − | /bin/mount | + | /bin/mount |
| − | /bin/su | + | /bin/su |
| − | /bin/ping6 | + | /bin/ping6 |
| − | /bin/fusermount | + | /bin/fusermount |
| − | /bin/ping | + | /bin/ping |
| − | /bin/umount | + | /bin/umount |
| − | /sbin/mount.ecryptfs_private | + | /sbin/mount.ecryptfs_private |
Note that the "2>/dev/null" removes those entries that have an error of "Permission Denied" | Note that the "2>/dev/null" removes those entries that have an error of "Permission Denied" | ||
| − | 11. Find readonly files | + | |
| + | ==11. Find readonly files== | ||
Find all Read Only files. | Find all Read Only files. | ||
| − | $ find /etc -maxdepth 1 -perm /u=r | + | $ find /etc -maxdepth 1 -perm /u=r |
| − | /etc | + | /etc |
| − | /etc/thunderbird | + | /etc/thunderbird |
| − | /etc/brltty | + | /etc/brltty |
| − | /etc/dkms | + | /etc/dkms |
| − | /etc/phpmyadmin | + | /etc/phpmyadmin |
| − | ... output truncated ... | + | ... output truncated ... |
| − | 12. Find executable files | + | ==12. Find executable files== |
The following command will find executable files | The following command will find executable files | ||
| − | $ find /bin -maxdepth 2 -perm /a=x | + | $ find /bin -maxdepth 2 -perm /a=x |
| − | /bin | + | /bin |
| − | /bin/preseed_command | + | /bin/preseed_command |
| − | /bin/mount | + | /bin/mount |
| − | /bin/zfgrep | + | /bin/zfgrep |
| − | /bin/tempfile | + | /bin/tempfile |
| − | ... output truncated ... | + | ... output truncated ... |
Search Files Based On Owners and Groups | Search Files Based On Owners and Groups | ||
| − | 13. Find files belonging to particular user | + | |
| + | ==13. Find files belonging to particular user== | ||
To find all or single file called tecmint.txt under /root directory of owner root. | To find all or single file called tecmint.txt under /root directory of owner root. | ||
| − | $ find . -user bob | + | $ find . -user bob |
| − | . | + | . |
| − | ./abc.txt | + | ./abc.txt |
| − | ./abc | + | ./abc |
| − | ./subdir | + | ./subdir |
| − | ./subdir/how.php | + | ./subdir/how.php |
| − | ./abc.php | + | ./abc.php |
We could also specify the name of the file or any name related criteria along with user criteria | We could also specify the name of the file or any name related criteria along with user criteria | ||
| − | $ find . -user bob -name '*.php' | + | $ 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. | 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 | + | |
| + | ==14. Search files belonging to group== | ||
Find all files that belong to a particular group. | Find all files that belong to a particular group. | ||
| − | # find /var/www -group developer | + | # find /var/www -group developer |
Did you know you could search your home directory by using the ~ symbol ? | Did you know you could search your home directory by using the ~ symbol ? | ||
| − | $ find ~ -name "hidden.php" | + | $ find ~ -name "hidden.php" |
Easy!! | Easy!! | ||
| Line 248: | Line 251: | ||
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 | 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 | + | |
| + | ==15. Find files modified N days back== | ||
To find all the files which are modified 50 days back. | To find all the files which are modified 50 days back. | ||
| − | # find / -mtime 50 | + | # find / -mtime 50 |
| − | 16. Find files accessed in last N days | + | ==16. Find files accessed in last N days== |
Find all files that were accessed in the last 50 days. | Find all files that were accessed in the last 50 days. | ||
| − | # find / -atime 50 | + | # find / -atime 50 |
| − | 17. Find files modified in a range of days | + | ==17. Find files modified in a range of days== |
Find all files that were modified between 50 to 100 days ago. | Find all files that were modified between 50 to 100 days ago. | ||
| − | # find / -mtime +50 –mtime -100 | + | # find / -mtime +50 –mtime -100 |
| − | 18. Find files changed in last N minutes. | + | ==18. Find files changed in last N minutes.== |
Find files modified within the last 1 hour. | Find files modified within the last 1 hour. | ||
| − | $ find /home/bob -cmin -60 | + | $ find /home/bob -cmin -60 |
| − | 19. Files modified in last hour | + | ==19. Files modified in last hour== |
To find all the files which are modified in last 1 hour. | To find all the files which are modified in last 1 hour. | ||
| − | # find / -mmin -60 | + | # find / -mmin -60 |
| − | 20. Find Accessed Files in Last 1 Hour | + | ==20. Find Accessed Files in Last 1 Hour== |
To find all the files which are accessed in last 1 hour. | To find all the files which are accessed in last 1 hour. | ||
| − | # find / -amin -60 | + | # find / -amin -60 |
Search files and directories based on size | Search files and directories based on size | ||
| − | 21. Find files of given size | + | |
| + | ==21. Find files of given size== | ||
To find all 50MB files, use. | To find all 50MB files, use. | ||
| − | # find / -size 50M | + | # find / -size 50M |
| − | 22. Find files in a size range | + | ==22. Find files in a size range== |
To find all the files which are greater than 50MB and less than 100MB. | To find all the files which are greater than 50MB and less than 100MB. | ||
| − | $ find / -size +50M -size -100M | + | $ find / -size +50M -size -100M |
| − | 23. Find largest and smallest files | + | ==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 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. | 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 | + | $ find . -type f -exec ls -s {} \; | sort -n -r | head -5 |
Similary when sorted in ascending order, it would show the smallest files first | Similary when sorted in ascending order, it would show the smallest files first | ||
| − | $ find . -type f -exec ls -s {} \; | sort -n | head -5 | + | $ find . -type f -exec ls -s {} \; | sort -n | head -5 |
| − | 24. Find empty files and directories | + | ==24. Find empty files and directories== |
The following command uses the "empty" option of the find command, which finds all files that are empty. | The following command uses the "empty" option of the find command, which finds all files that are empty. | ||
| − | # find /tmp -type f -empty | + | # find /tmp -type f -empty |
To file all empty directories use the type "d". | To file all empty directories use the type "d". | ||
| − | $ find ~/ -type d -empty | + | $ find ~/ -type d -empty |
Really very simple and easy | Really very simple and easy | ||
| − | Some advanced operations | + | |
| + | =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. | 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 | Here are some quick examples | ||
| − | 25. List out the found files | + | |
| + | ==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. | 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 {} \; | + | $ find . -exec ls -ld {} \; |
| − | drwxrwxr-x 4 enlightened enlightened 4096 Aug 11 19:01 . | + | drwxrwxr-x 4 enlightened enlightened 4096 Aug 11 19:01 . |
| − | -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:25 ./abc.txt | + | -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 16:48 ./abc |
| − | drwxrwxr-x 2 enlightened enlightened 4096 Aug 11 16:26 ./subdir | + | 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 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 29 Aug 11 19:13 ./abc.php |
| − | -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:25 ./cool.php | + | -rw-rw-r-- 1 enlightened enlightened 0 Aug 11 16:25 ./cool.php |
| − | 26. Delete all matching files or directories | + | ==26. Delete all matching files or directories== |
The following command will remove all text files in the tmp directory. | The following command will remove all text files in the tmp directory. | ||
| − | $ find /tmp -type f -name "*.txt" -exec rm -f {} \; | + | $ 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. | The same operating can be carried out with directories, just put type d, instead of type f. | ||
| Line 347: | Line 354: | ||
Lets take another example where we want to delete files larger than 100MB | 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 {} \; | + | $ find /home/bob/dir -type f -name *.log -size +10M -exec rm -f {} \; |
| − | Summary | + | ==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. | 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. | ||
Revision as of 11:54, 18 June 2017
sumber: http://www.binarytides.com/linux-find-command-examples/
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
Basic examples
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.
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 ".*"
Find files based on permissions
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 ...
Search Files Based On Owners and Groups
13. Find files belonging 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
Search files and directories based on size
21. Find files of given 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.