Wouldn't (?:\.\\|\./) mean "full stop, then either backslash or dot, then forward slash"? ... Or does a | placed within grouping parentheses always match the entire first/second half of the grouping?

It is second case: [.\\] is one group of regex, [./] is the other.

To match per your first query, regex would be qr{[.] (?: \\ | . ) /}x (which I would rather write as qr{[.] [.\\] /}x but that is besides the point).

In reply to Re^3: Regex failing when the line starts with "./" by Anonymous Monk
in thread Regex failing when the line starts with "./" by perl_mystery

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