system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how does file compression work? As in .zip, .rar, etc.
gpt
To give a really simple example....

Say you want to compress a text file that contains:

"AAAAAAAAAAAAAAAAAAAA"

Originally that file is 20 characters long. You can compress it by doing this instead:

"Ax20"

You've now reduced it to 4 characters with no loss of information.

In reality, compression works similarly to this, it looks for patterns that can de described in a shorter way. For example it may take less space to say the word "and" appears at certain locations than to actually list the word again and again.