Simple Guide to Find Command

The find command is one of the most powerful tools in the Linux system. It searches for files and directories based on their permissions, type, ownership, size, and more. It can also be combined with other tools such as grep or sed

Command syntax

The general syntax for the find command is as follows:

find [options] [path...] [expressio]

• The options attribute controls the treatment of the symbolic links
• The path... attribute defines the starting directory or directories where find will search the files
• The expression attribute is made up of options, search patterns, and actions separated by operators

Find files by name

To find a file by its name, use the -name option followed by the name of the file you are searching for. To run a case-insensitive search, change the -name option with -iname

For example:

find /home/username -type f -name document.pdf

Find files by extension

Searching for files by extension is the same as searching for files by name

For example:

find /var/log/nginx -type f -name '*.log.gz'

Find files by type

To search for fiels based on their type, use the -type option and one of the following descriptors to specify the type:

• f: a regular file
• d: directory
• l: symbolic link
• c: character devices
• b: block devices
• p: named pipe (FIFO)
• s: socket

For example:

find /var/www/my_website -type d -exec chmod 0755 {} \;
find /var/www/my_website -type f -exec chmod 0644 {} \;

Find files by size

To find files based on the file size, pass the -szie parameter along with the size criteria. You can use the following suffixes to specify the file size

• b: 512-byte blocks (default)
• c: byte
• w: two-byte words
• k: kilobytes
• M: Megabytes
• G: Gigabytes

For example

find /tmp -type f -size 1024c

The find command also allows you to search for files that are greater or less than a specified size

find . -type f -size -1M	// less than 1M
find . -type f -size +1M	// greater than 1M
find . -type f -size +1M -size -2M	// between 1 and 2M

Find files by modification date

To search for files based on their last modification, access, or changed time, we can use a syntax similar to size. To use the plus and minus symbols for "greater than" or "less than" and use the -daystart option

For example:

find /home -name "*.conf" -mtime 5	// search for files that has been modified in the last five days
find /home -mtime +30 -daystart // search for files that were modified 30 or more days ago

Find files by permissions

The -perm option allows you to search for files based on the file permissions

For example, to find all files with permissions of exactly 644 inside the /var/www/html directory

find /var/www/html -perm 644

You can prefix the numeric mode with minus - or flash /. When slash / is used as the prefix, then at least one category (user, group, or others) must have at least the respective bits set for a file to match. If minus - is used as the prefix, then for the file to match, at least the specified bits must be set

Find files by owner

To find files owned by a particular user or group, use the -user and -group options

find / -user username

Find and delete files

To delete all matching files, append the -delete option to the end of the match expression

find /var/log/ -name `*.temp` -delete

Find and execute commands

For example renaming files from js extension to tsx extension:

find ./ -depth -name "*.tsx" -exec sh -c 'mv "$1" "${1%.tsx}.js"' _ {} \;

Symbolic links

To specify the behavior of find about the symbolic links, we can use the options -H, -L, and -P. They must appear before the first path name

• -P: Never follow symbolic links. This is the default behavior
• -L: Follow symbolic links
• -H: Do not follow symbolic links, except while processing the command line arguments

Other options

There are many other options for fine tuning. The debugger, optimizer and print function are especially useful.

References

1. linuxize
2. manpage