Basic manipulation.
WHAT touch DOES
Creates an empty file, or updates a file's timestamp.
WHAT mkdir DOES
Creates a directory.
WHAT THE PARENTS OPTION ADDS
Creating every directory in a path at once, without error if they exist.
WHAT cp DOES
Copies.
WHAT THE RECURSIVE OPTION IS FOR
Copying directories.
WHAT THE PRESERVE OPTION DOES
Keeps permissions, ownership and timestamps.
WHY THAT MATTERS ON A SERVER
A copy with wrong ownership frequently stops a site working.
WHAT mv DOES
Moves, and also renames.
WHY THEY ARE THE SAME OPERATION
Renaming is moving within the same directory.
WHAT rm DOES
Deletes, permanently and immediately.
WHAT THERE IS NO
Recycle bin.
WHAT THE RECURSIVE AND FORCE OPTIONS TOGETHER DO
Delete a directory and everything in it without asking.
WHY THAT COMBINATION DESERVES RESPECT
It is the command that has destroyed more servers than any other.
WHAT TO DO BEFORE RUNNING IT
Run ls on the same path first, and read what it lists.
WHAT TO NEVER DO
Use it with a variable that might be empty Use it with a wildcard you have not checked
WHAT TO PREFER WHERE POSSIBLE
Moving to a temporary directory instead of deleting.
