If you read the contents of your config.txt file into a variable, you can use a regex containing "Link encap:" to capture the IPs:

use Modern::Perl;

my $data = do { local $/; <DATA> };
my ( $eth0, $lo ) =
  $data =~ /Link encap:.+inet addr:([\d.]+).+inet addr:([\d.]+)/s;

say $eth0 ? "eth0 => $eth0\nlo => $lo" : 'not ethernet';

__DATA__
eth0      Link encap:Ethernet  HWaddr 00:0C:29:0F:9B:82
          inet addr:192.168.8.76  Bcast:192.168.8.255  Mask:255.255.25
+5.0
          inet6 addr: fe80::20c:29ff:fe0f:9b82/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:280252 errors:0 dropped:0 overruns:0 frame:0
          TX packets:106184 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:35501675 (33.8 MiB)  TX bytes:11696548 (11.1 MiB)
          Base address:0x1080 Memory:f4820000-f4840000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:4664 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4664 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:7952486 (7.5 MiB)  TX bytes:7952486 (7.5 MiB)

[download]

Output:

eth0 => 192.168.8.76
lo => 127.0.0.1

[download]

"not ethernet" will be printed if "Link encap:" is not in the config.txt contents.

Hope this helps!

In reply to Re: how to check condition and then pattern match by Kenosis
in thread how to check condition and then pattern match by laksh

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