Search and find files by modification date
find ./ -mtime -75 | more
Command: find [man page]
Destination: ./ [current directory onwards]
Option: -mtime [modification time] -n [days]
If you expect to find many files, use more to scroll (use Enter key) thru the result.
Command: more [man page]
A not traditional cheat sheet for Linux beginners can be found here