Finding a file by name from the Linux command line

If you search a lot, locate is near enough instant because it reads from a database instead of crawling the disk. sudo apt install plocate, then locate notes.txt. Brand new files won't be in it until the database updates, sudo updatedb forces that.

find / -iname "notes.txt" 2>/dev/null -iname ignores case, the 2>/dev/null hides all the permission denied noise. Wildcards work too, like "*report*". Searching from / is slow, so start from your home folder if you know it's in there.