Oct 25, 2017 Storing data in cache makes your Mac run faster because it can obtain the data quickly. Sometimes the cache gets corrupt, though, because of software updates, conflicts, and unexpected quits, and this can cause problems. Find out how to delete the library cache occasionally to maintain your Mac’s performance.+ +How to Delete Cache+.

Don't modify the Cleanup Script - things in /System are NOT guaranteed to not be deleted or changed by Software Update.

Jun 06, 2017 How to clear your cache on Mac OS X Os Sierra Version 10.12.3 including how to clear your Library cache and how to clear the main Mac OS X system caches.
Apr 14, 2017 Caches store information that Mac system or applications need to quickly launch service. Generally, you may not notice this part of data in your MacBook Air until you need to delete unneeded files to get more space or clear cache to fix software problems.
/Library/Caches Make sure that once you have finished clearing out these caches for additional hard drive space, you empty out your Trash. To do this, Control-click on the Trash icon in the dock and select “Empty Trash.” Restart your Mac afterward so your Mac can begin to create new, fresh cache files.
Jan 20, 2017 To empty or clear the cache in Safari 9 & 10 on Mac: 1. Click “Safari” in the upper right hand corner. Choose “Preferences”. Click the “Advanced” icon. At the bottom of the “Advanced” options page, select of check “Show Develop Menu In Menu Bar. Close the options window.

Clear Library Cache Mac

Instead, make your own startup item in /Library/StartupItems

Outlook Mac Empty Cache

sudo mkdir /Library/StartupItems/CacheCleaner

You may have to create /Library/StartupItems - I don't remember if OS X ships with an empty one by default or not. If you do have to create it, remember that there is not a space between Startup and Items

Create /Library/StartupItems/CacheCleaner/CacheCleaner with the following contents:

#!/bin/sh
. /etc/rc.common
##
# Start mail server
##
ConsoleMessage 'Cleaning System Cache Files'
rm -fr /System/Library/Caches/*
rm -fr /Library/Caches/*

Don't forget to chmod 755 /Library/StartupItems/CacheCleaner/CacheCleaner or the startup item won't load.

Now create /Library/StartupItems/CacheCleaner/StartupParameters.plist with the following contents:

{
Description = 'Cache Cleaner';
Provides = ('CleanCache');
Requires = ('Cleanup');
Uses = ('Cleanup');
Preference = 'None';
OrderPreference = 'Early';
Messages =
{
start = 'Cleaning System Cache Files';
stop = 'Cleaning System Cache Files';
};
}

This way you don't have to worry about system updates (like Jaguar) trashing your startup item. The line Requires = ('Cleanup'); will tell OS X to run your startup item some time after the standard Cleanup startup item.

Now to clean your personal caches, you're better off using an applescript that launches during login.

Open Script Editor, and put the following lines into a new script:

do shell script 'rm -rf ~/Library/Preferences/Explorer/Download*Cache'
do shell script 'rm -rf ~/Library/Caches/*'
-- Uncomment the next line if you want to nuke your IE History as well
-- do shell script 'rm -rf ~/Library/Preferences/Explorer/History.html'

Save the script somewhere, then go into the Login pane of System Preferences and add the new script to your login items.

jpb

Empty Sierra Mac Library Cache