For the basic [or infuriating] linux details I constantly find myself needing.

change file permissions the octal goes like this: [user][group][others] the user is the owner of the file. Is there a way to have multiple owners and multiple groups?
You are setting bits using hexadecimals for three octals. Each one works the same way. Each bit of the octal represents a permission that you can have, like read, write or execute. It's easier just to use the letter designations for these like I did in the example below.

use ls -l [filename] to see what permissions there are already.

chmod u+rwx file.txt

search for files by file name. example: find ./ -name "fishguy*"

when copying fails, delete the files in the Downloads folder using find and then download the latest version following the instructions on this page: https://makemkv.com/forum/viewtopic.php?f=3&t=224

• Cut: Ctrl + k
• copy: Alt + ^ i.e. Alt + Shift + 6
• paste Ctrl + u
• save: Ctrl + o
• select all: Alt + a

AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAGH! [loads a bullet, spins the chamber.]