That said, no, those are not the same: while(<FH>){...} assigns to $_, but $line=<FH> assigns to $line. Other than that, they are the same.

Actually, a crucial difference is that while(<FH>){...} gets interpreted by Perl as:

    while (defined($_ = <FH>)) { ... }
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which effectively ends the while loop once there are no more lines to be read from the filehandle. With $line=<FH>, we need to check for defined-ness.

my @lines = do { open my $fh, '<', $file or die "$file: $!\n"; <$fh> };

Another way:

my @lines = do { local @ARGV = $file; <> };
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