Paolo Bonzini <[EMAIL PROTECTED]> writes: > Yes, it is undefined
I don't see why 's&foo&\&&' is undefined. The POSIX standard says: Any character other than backslash or <newline> can be used instead of a slash to delimit the BRE and the replacement. Within the BRE and the replacement, the BRE delimiter itself can be used as a literal character if it is preceded by a backslash. Therefore, preceding & by a backslash makes it a "literal character", i.e., a character that is not special. Where's the ambiguity? Even if the standard were ambiguous (which I don't yet see), there is a practical advantage to behaving compatibly with other 'sed' implementations in this area. Anyway, if you like, I can file an interpretation request with the POSIX folks about this.
