为什么此egrep命令在我的Shell中有效，而在Perl中却无效？

Question

The following command works on the command line in Linux:

egrep -r -i -I -H -A5 "^name#maria.*?#[0-9]{4}#.*?#.*?#.*?$" .

But when I use it inside a Perl script, it doesn't return anything. This is the Perl code:

my @rows = `egrep -r -i -I -H -A5 "^name#maria.*?#[0-9]{4}#.*?#.*?#.*?$" .`;

What am I doing wrong?

Answer 1

$" is a perl variable and is being expanded inside the backticks. You'll need to escape the dollar

my @rows = qx{egrep -r -i -I -H -A5 "^name#maria.*?#[0-9]{4}#.*?#.*?#.*?\$" .};

I'm using qx{} instead of the less-visible backticks.

---

Another method, use open and pass each argument as a separate parameter:

use autodie qw/open close/;
my @command = ('egrep','-r','-i','-I','-H','-A5','^name#maria.*?#[0-9]{4}#.*?#.*?#.*?$','.');
open my $pipe, '-|', @command;
chomp( my @rows = <$pipe> );
close $pipe;