Re: grep in line and print

[Athanasius]

Hello justbow, and welcome to the Monastery!

Perhaps this is what you’re looking for:

#! perl
use strict;
use warnings;

while (my $line = <DATA>)
{
    if ($line =~ /C4:46:19:75:C1:55/)
    {
        print "ID = ", (split /\s+/, $line)[0], "\n";
    }
}

__DATA__
SS-ID VLAN MAC TIME IP RSSI MODE UAPSD BW GI WMOS DHCP IDENTITY
----- ---- --- ---- -- ---- ---- ----- -- -- ---- ---- --------
1-1 0 C4:46:19:75:C1:55 23m 192.168.5.253 -24 bgn no 20 S 4.9 ack*
1-2 0 5C:57:C8:69:8C:1E 3s 192.168.5.254 -38 bg no 20 L 4.8 ack*

Output:

12:28 >perl 495_SoPW.pl
ID = 1-1

12:28 >

Update: The following is probably clearer:

#! perl
use strict;
use warnings;

while (my $line = <DATA>)
{
    chomp $line;
    my @recs = split /\s+/, $line;

    if ($recs[2] eq 'C4:46:19:75:C1:55')
    {
        print "ID = ", $recs[0], "\n";
    }
}

__DATA__
SS-ID VLAN MAC TIME IP RSSI MODE UAPSD BW GI WMOS DHCP IDENTITY
----- ---- --- ---- -- ---- ---- ----- -- -- ---- ---- --------
1-1 0 C4:46:19:75:C1:55 23m 192.168.5.253 -24 bgn no 20 S 4.9 ack*
1-2 0 5C:57:C8:69:8C:1E 3s 192.168.5.254 -38 bg no 20 L 4.8 ack*

(Same output.)

See split.

Hope that helps,

[justbow]

Hello Athanasius, Thanks for the suggestion, But im still getting the error :D I'm trying the code :

#! perl
use strict;
use warnings;

$allmac = "~/temp/allmac.txt";
print $allmac;
while (my $line = $allmac)
{
    if ($line =~ /C4:46:19:75:C1:55/)
    {
        $id = (split /\s+/, $line)[0];
        print "ID = $id\n";
    }
}

And getting error :

Global symbol "$allmac" requires explicit package name at ./filtermac.
+pl line 5.
Global symbol "$allmac" requires explicit package name at ./filtermac.
+pl line 6.
Global symbol "$allmac" requires explicit package name at ./filtermac.
+pl line 7.
Global symbol "$id" requires explicit package name at ./filtermac.pl l
+ine 11.
Global symbol "$id" requires explicit package name at ./filtermac.pl l
+ine 12.
Execution of ./filtermac.pl aborted due to compilation errors.

[Athanasius]

With use strict in effect, you need to declare your variable names:

my $allmac = ...
...
        my $id = ...

But the line:

while (my $line = $allmac)

won’t work: it’s assigning the file name to $line, but it needs to call readline on a file handle, like so:

open (my $fh, '<', $allmac) or die "Can't open file '$allmac' for read
+ing: $!";

while (my $line = <$fh>)
{
    ....

Applying the diamond operator to a filehandle: <$fh> is the standard way to call readline in Perl. See readline and I/O Operators; also open and perlopentut.

Hope that helps,