find
Tested find examples: name and type filters, size and age, permissions, -exec vs -delete, and safe scripting patterns.
files
Working with files and directories
tar
Tested tar examples: create, list, and extract archives, choose a compression format, and verify integrity.
Bulk rename a batch of files
Rename many files at once with a plain bash loop, safely handling spaces and previewing changes before committing.
Copy files between two machines over SSH
Transfer a file or directory tree between two machines with scp or rsync, and resume an interrupted transfer without starting over.
Find the largest files on disk
Locate what's actually eating your disk space, from a whole filesystem down to one directory.