Вывод perl grep из файла

Использование qx было бы сложным.

use File::Basename     qw( basename );
use String::ShellQuote qw( shell_quote );

my $file_qfn = "...";

my $name;
{
   my @cmd = ( "grep", "-oP", "-m", "1", '^NAME\s+=\s+\K(.*)', $file_qfn );
   my $cmd = shell_quote( @cmd );
   $name = qx($cmd);
   die "Can't spawn shell: $!\n" if $? == -1;
   die "Shell killed by signal ".( $? & 0x7F )."\n" ) if $? & 0x7F;
   die "Shell exited with error ".( $? >> 8 )."\n" ) if $? >> 8;
   chomp( $name );
}

my $value;
{
   my $name_pat = quotemeta( $name );
   my @cmd = ( "grep", "-oP", "-m", "1", "^$name_pat\\s+=\\s+\\K(.*)", $file_qfn );
   my $cmd = shell_quote( @cmd );
   $value = qx($cmd);
   die "Can't spawn shell: $!\n" if $? == -1;
   die "Shell killed by signal ".( $? & 0x7F )."\n" ) if $? & 0x7F;
   die "Shell exited with error ".( $? >> 8 )."\n" ) if $? >> 8;
   chomp( $value );
}

my $base = basename( $value );

Мы можем избежать оболочки и упростить вещи, используя capturex.

use File::Basename      qw( basename );
use IPC::System::Simple qw( capturex );

my $file_qfn = "...";

my $name;
{
   my @cmd = ( "grep", "-oP", "-m", "1", '^NAME\s+=\s+\K(.*)', $file_qfn );
   $name = capturex( @cmd );
   chomp( $name );
}

my $value;
{
   my $name_pat = quotemeta( $name );
   my @cmd = ( "grep", "-oP", "-m", "1", "^$name_pat\\s+=\\s+\\K(.*)", $file_qfn );
   $value = capturex( @cmd );
   chomp( $value );
}

my $base = basename( $value );

Но я думаю, что идея создавать детей для этой задачи неприятна.

use File::Basename qw( basename );
use File::Slurper  qw( read_text );

my $file_qfn = "...";

my $file = read_text( $file_qfn );

my ( $name ) = $file =~ /^NAME\s+=\s+\K(.*)/m
   or die( "Can't find `NAME` field\n" );
my ( $value ) = $file =~ /^\Q$name\E\s+=\s+\K(.*)/m
   or die( "Can't find `$name` field\n" );

my $base = basename( $value );

На самом деле я бы использовал что-то вроде следующего:

use File::Basename qw( basename );

my $file_qfn = "...";

open( my $fh, '<', $file_qfn )
   or die( "Can't open file \"$file_qfn \": $!\n" );

my %data;
while ( <$fh> ) {
   chomp;
   my ( $k, $v ) = split( /\s+=\s+/, $_, 2 );
   $data{ $k } = $v;
}

defined( my $name = $data{ NAME } )
   or die( "Can't find `NAME` field\n" );
defined( my $value = $data{ $name } )
   or die( "Can't find `$name` field\n" );
my $base = basename( $value );