perl行计数包含特定文本的文件

Question

Basically I want to count the number if lines which contain the word Out.

my $lc1 = 0;
open my $file, "<", "LNP_Define.cfg" or die($!);
#return [ grep m|Out|, <$file> ]; (I tried something with return to but also failed)
#$lc1++ while <$file>;
#while <$file> {$lc1++ if (the idea of the if statement is to count lines if it contains  Out)
close $file;
print $lc1, "\n";

Answer 1

The command line might be potential option for you too:

perl -ne '$lc1++ if /Out/; END { print "$lc1\n"; } ' LNP_Define.cfg

The -n assumes a while loop for all your code before END .
The -e expects code surrounded by ' ' .

The $lc1++ will count only if the following if statement is true.

The if statement runs per line looking for " Out ".

The END { } statement is for processing after the while loops ends. Here is where you can print the count.

Or without the command line:

my $lc1;
while ( readline ) {
    $lc1++ if /Out/; 
}    
print "$lc1\n";

Then run on the command line:

$ perl count.pl LNP_Define.cfg

Answer 2

使用index ：

0 <= index $_, 'Out' and $lc1++ while <$file>;