how to check condition and then pattern match

laksh has asked for the wisdom of the Perl Monks concerning the following question:

My config.txt file look like this

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]

my script file look like this

open FILE,"config.txt" or die "cannot open file : $!";
my $interface; # declare the variable
while(<FILE>) {
 
 $interface = $1 if /^([\S]+)/;
 print "$interface => $1\n" if /inet addr:([0-9.]+)/;
 
}
[download]

need help I need to check the condition if line contain "Link encap:" then get the same output as shown else its say "not ethernet" but its not happening

my output is: 

eth0 => 192.168.8.76
lo => 127.0.0.1
[download]

Comment on how to check condition and then pattern match Select or Download Code

Replies are listed 'Best First'.
Re: how to check condition and then pattern match by aitap (Curate) on Aug 23, 2012 at 10:33 UTC
Extend the second regexp to match only lines where "Ethernet" string is present. Something like this: `^([\S]+) ... Ethernet`. See perlretut for more information. Sorry if my advice was wrong.	[reply] [d/l]
Re: how to check condition and then pattern match by Kenosis (Priest) on Aug 23, 2012 at 15:23 UTC
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!	[reply] [d/l] [select]
Re: how to check condition and then pattern match by afoken (Chancellor) on Aug 24, 2012 at 04:37 UTC
See also need to remove the extra line in regular expression, same problem, same user. By the way: Do you use two or more accounts? (ulaksh, laksh) Alexander -- Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)	[reply]
Re: how to check condition and then pattern match by pvaldes (Chaplain) on Aug 23, 2012 at 15:32 UTC
Seems that you want to parse an ifconfig output: `use Net::Int::Stats;`	[reply] [d/l]
Re: how to check condition and then pattern match by cheekuperl (Monk) on Aug 23, 2012 at 10:31 UTC
What have you tried?	[reply]