Linux Commands – Delete Files Older Than X

1. Overview

We often need to tidy up files on our workstations or servers. Our
applications may produce logs or temporary files. One common use case is
to delete files that are above a certain age.

In this tutorial, we’ll look at ways to delete files by age on Linux.
These commands may also work in other POSIX shells.

[[deleting files]]
=== 2. Finding and Deleting Files

We’re going to need to find the files that match our criteria in order
to apply the delete action.

For this, we’ll use the
find
command. The find command even provides a delete capability that
we can use.

2.1. Delete Files Older than X Minutes

Let’s start by using find to delete files whose file names start with
access and end with .log, and which are older than 15 minutes:

find . -name "access*.log" -type f -mmin +15 -delete

Let’s have a closer look at how this command is constructed.

First, we’ve specified the starting point for files lookup, it’s the
current working directory “.”.

Then, we have the file name criteria prefixed with the -name switch.

The switch -type f means we want to look for files only.

The -mmin stands for the modification time, and +15 means we want
files that were last modified at 15 minutes ago or earlier.

The action flag -delete asks find to delete all the files it finds.
We should note that this will look recursively through the file system
hierarchy, starting from the current working directory.

2.2. Delete Files Older than X Days

It only takes a small change to the find command to switch from
minutes to days:

find . -name "access*.log" -type f -mtime +5 -delete

Here, the -mtime switch says we want to delete files that were
modified at least 5 days ago.

2.3. Delete Files Older than X days With an Older Version of find

Using older distributions, the find tool might not have the -delete
switch.

In this instance there’s another way:

find . -name "access*log" -exec rm {} \;

In this version, the -exec switch allows us to use the rm command
on each file found.

2.4. Delete Files Older than X days With a Prompt

We might be concerned that an incorrectly constructed delete command
might end up with deleting wrong files. A small variation of the above
command will prompt us before deletion.

Let’s add the -i switch to the rm command:

find . -name "access*log" -exec rm -i {} \;

This way, we can decide which files get deleted.

3. Avoiding Accidental File Deletion

Deleting files is fairly easy, but we must remember we’re doing it for
all the files that match the find predicate. This means a simple typo
or unexpected order of the command line switches might cause unexpected
damage.

As an example, let’s look at the following command:

find . -delete -name file.txt

We might assume that this would delete only file.txt from the current
working directory. However, since the -delete switch comes first, the
-name is ignored. This mistake will delete everything in our current
directory!

Here are some general rules we should follow to improve safety when
deleting with find:

  • Make sure the find command is correct by previewing it, running it
    without the -delete switch

  • Always check the -delete option is at the end of the find
    arguments

  • Never delete the files as the root user unless absolutely necessary

4. Summary

In this tutorial, we’ve looked at how we can delete files older than
some period of time.

Next, we looked at what might go wrong if given switches are out of the
necessary order.

Finally, we’ve had a brief look at general rules we should follow when
running such commands on our system.

The find command is very handy and has lots of additional switches.
We can find out more about it with either man find or find –help.

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