% sort [filename] % sort [filename] [filename] % cat [filename] | sort 1 c 3 e 12 a 9 x 9 d 1 c 20 f 5 o % sort [file1] 1 c 12 a 3 e 9 x % sort -n [file1] 1 c 3 e 9 x 12 a % sort [file1] [file2] 1 c 1 c 12 a 20 f 3 e 5 o 9 d 9 x % sort -u [file1] [file2] 1 c 12 a 20 f 3 e 5 o 9 d 9 x % sort -un [file1] [file2] 1 c 3 e 5 o 9 d 12 a 20 f % sort +1 [file1] 12 a 1 c 3 e 9 x