I think ^help^ does the same thing. The bash manual says ^string1^string2^ is equivalent to !!:s/string1/string2/ where / can be any delimiter, and the

I think ^help^ does the same thing. The bash manual says ^string1^string2^ is equivalent to !!:s/string1/string2/ where / can be any delimiter, and the "final delimiter is optional if it is the last character of the event line." So, not so surprising that the third ^ is optional too. TIL: In either of these forms, if string1 is empty, it is set to the last string1, or, "if no previous history substitutions took place, the last string in a !?string[?] search." E.g. $ echo foofoo foofoo $ ^foo^ echo foo foo $ ^^bar echo bar bar