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in reply to Do not understand code

unlink $file if /.BGV/; ... what does this 'if' means? What condition is it?

The if after a statement is a statement modifier, it is the equivalent of if (/.BGV/) { unlink $file }. The condition is equivalent to $_ =~ /.BGV/, that is, match the special variable $_ against the regex /.BGV/. The special variable $_ gets set in several places, one very common one is the while (<$filehandle>) { ... } loop, see I/O Operators. That line of code in English: If the string stored in $_ contains the four-character sequence of any character (except newline) followed by the string 'BGV', then unlink (delete) the file whose name is given in the string $file.

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Re^2: Do not understand code
by BlackKnait (Novice) on Sep 28, 2017 at 10:20 UTC
    Thanks for this detailed answer. I knew its possible to ask for a condition like $_ ~= <regex> - but this notation is new for me. With this information I understand this snippet.
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      Note that you reversed the operator. It’s not ~=, it’s =~.

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