find

find has many options for specifying files
e.g. run rm on all files that are older than 30 days and prompt to confirm % find . -ctime +30 -print -ok -exec rm {} \;
e.g. list files that don't end in ".txt" and ".doc" % find . -not \( -name "*.txt" -o -name "*.doc" \)
e.g. list files that are symbolic links under /tmp % find /tmp -type l