. dot matches any single character ...

∖* match zero or more occurences of (char or something) ...

∖+ match one or more occurences of (char or something) ...

∖? Match 0 or 1 instance of (character)

[abcdef] Match any character enclosed in [] (in this instance, a b c d e or f) ranges of characters such as [a-z] are permitted. The behaviour of this deserves more description. See the page on grep for more details about the syntax of lists. to include `]' in the list, make it the first char, to include `-' in the list, make it the first or last