IBIZA desentol /tarifa1/users/desentol/mlima/dados/input > ls | grep -oE "\.\w+$" | sort -u grep: illegal option -- o usage: grep [-E | -F] [-c|-l|-q] [-insvxbhwy] [-p parasep] -e pattern_list... [-f pattern_file...] [file...] usage: grep [-E | -F] [-c|-l|-q] [-insvxbhwy] [-p parasep] [-e pattern_list...] -f pattern_file... [file...] usage: grep [-E | -F] [-c|-l|-q] [-insvxbhwy] [-p parasep] pattern [file...]