What does this UNIX command do? ls –lrt | grep tmp > z.z?

Question

Thanks all

Answer 1

list files with detail, sort by modification time, recurse subdirectories containing the letters "tmp" and store those filenames in a file called z.z

Answer 2

Do a directory listing, long or detailed (-l) in reverse order (-r) by modification time (-t) ; pipe (|) the results through grep to find only those that contain "tmp" and redirect the output (>) to file z.z

Answer 3

'ls' lists files in the current directory. the '| grep xxxxx' part means it will "grep" (search, essentially) for things in the list that match your search term and only list those.

the '-lrt' part are flags for the 'ls' command.

type "man ls" into your unix terminal for more specifics.

EDIT: breakdown of the '-lrt' flags: 'l' outputs the list in a long format (more info per result), 'r' reverses the list output (z-a instead of a-z), and 't' sorts by last modified—which, of course, is reversed by the 'r' flag. so '-lrt' returns a list of the files in reverse chronological order.