Mastering the Linux find Command: 7 Powerful Use Cases for Devs

It can be said with confidence that the find command is one of the operations every Linux backend developer must know, unless you are using Windows Server.

It is also a hot topic in technical interviews. Consider this interview question:

If your Linux server has a directory named logs, how would you delete log files in that directory whose last access time is more than one year ago?

The answer is to first cd into the directory, then run the following command: find . -type f -atime +365 -exec rm -rf {} \; If you haven’t fully understood the command above, don’t worry. This article introduces seven practical uses of the find command, and you will master it by the end. If you already know it, the article serves as a good review.

Find by name or regular expression

Start with the simplest usage. To search for a file by a specific name: find . -name test.txt To find all PDF books using a regular expression: find ./yang/books -name "*.pdf" Specifying the file type makes the intent clearer:

find ./yang/books -type f -name "*.pdf"

Find different types of files

Besides regular files, you can search for other file types using the -type option.

For directories: find . -type d -name "yang*" For symbolic links:

find . -type l -name "yang*"

Find files by timestamp

Linux tracks three timestamps for each file:

atime : last time the file was read.

mtime : last time the file content was modified.

ctime : last time the file’s metadata (owner, permissions, etc.) changed.

To search for files whose access time is older than one year: find . -type f -atime +365 To find files whose modification time is exactly five days ago (no + sign): find . -type f -mtime 5 To find files whose change time is between five and ten days ago:

find . -type f -ctime +5 -ctime -10

Find files by size

The -size option lets you search by file size. Units are:

b: 512‑byte blocks (default)
c: bytes
w: two‑byte words
k: kilobytes
M: megabytes
G: gigabytes

For example, to find files between 10 MB and 1 GB:

find . -type f -size +10M -size -1G

Find files by permissions

Controlling file permissions is a key task for Linux administrators. Use -perm to locate files with specific permissions: find . -type f -perm 777 This command finds all files that have read, write, and execute permissions for owner, group, and others.

Find files by ownership

Specify the owner with -user. For example, to find all files owned by user yang:

find -type f -user yang

Execute a command on found files

Often you want to perform an action on each matched file, such as deleting or inspecting it. The -exec option makes this easy.

Returning to the interview question, you can combine -exec with rm -rf: find . -type f -atime +365 -exec rm -rf {} \; The placeholder {} represents each file found; without it, the command would act on all files in the directory.

Try the following two commands to see the difference:

With placeholder: find . -type f -atime +5 -exec ls {} \; Without placeholder: find . -type f -atime +5 -exec ls \; The -exec command must end with a semicolon ( \;), which is escaped with a backslash to prevent the shell from interpreting it.

Conclusion

After learning the seven uses of the find command, the interview question becomes easy to solve. You can now write the answer clearly and explain it.

find . -type f -atime +365 -exec rm -rf {} \;