Make the LHS an array and grep the line you want then print it.

$ cat > tfile 
line1
line2
line3
$ perl -Mstrict -we '
> my @error1 = do
>    {
>        open my $fh, q{<}, q{tfile} or die $!;
>        grep m{2}, <$fh>;
>    };
> print @error1 ? qq{match found : @error1} : qq{nothing\n};'
match found : line2
$ cat > tfile
line1
line3
$ $ perl -Mstrict -we '
> my @error1 = do
>    {
>        open my $fh, q{<}, q{tfile} or die $!;
>        grep m{2}, <$fh>;
>    };
> print @error1 ? qq{match found : @error1} : qq{nothing\n};'
nothing
$
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I hope this is helpful.