Automatically delete files older than 3 hours macOS

Here is an example find command that you can modify to suit your needs:

find '/path/to/files/' -type f -name '*.jpg' -mmin +180 -delete

I'd use launchd to run it every 3 hours.

Here is an example .plist file that will run the find command every 3 hours using launchd:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.my.delete.every.three.hours</string>
    <key>ProgramArguments</key>
    <array>
        <string>/usr/bin/find</string>
        <string>/path/to/files/</string>
        <string>-type</string>
        <string>f</string>
        <string>-name</string>
        <string>*.jpg</string>
        <string>-mmin</string>
        <string>+180</string>
        <string>-delete</string>
    </array>
    <key>RunAtLoad</key>
    <false/>
    <key>StartInterval</key>
    <integer>10800</integer>
</dict>
</plist>

It would be saved in: $HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist

From Terminal:

touch "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist"
open -e "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist"

• Copy and paste example XML code into the opened TextEdit document:
• Modify as needed:
  • E.g. Change /path/to/files/ to the actual path.
  • E.g. Change *.jpg to the proper extension if not: jpg
• Save and close the document.

Continue in Terminal, to load the plist file:

launchctl load "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist"

To stop and unload the "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist" file use:

launchctl stop "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist"
launchctl unload "$HOME/Library/LaunchAgents/com.my.delete.every.three.hours.plist"