diff -y -W 200 file1 file2

Shows a side by side diff of 2 files with enough column width to see most of what I need usually.

I have actually aliased this command as diffy

ctrl-r

searching bash history

du -sh * | sort -h

shows size of all files and dirs in the current dir and sorts them in ascending order so you can easily see the largest files or dirt ant the end of the list

ls -ltr

Shows the most recently modified files at the end of the listing.