On 05/20/2007 11:37 PM, Dharshana Eswaran wrote:
Hi All,
The below code helps in reading a file in reverse:
use strict;
use warning;
open( FILE, "<$file_to_reverse" )
or die( "Can't open file file_to_reverse: $!" );
@lines = reverse <FILE>;
foreach $line (@lines) {
# do something with $line
}
But i am trying to grep for a string in the file and once i get the string,
I need to read few lines which occurs before the string. For eg:
typedef union
{
TYPE_T type;
MODE_T mode;
} CHANNEL_INFO_T;
Here, I grep for CHANNEL_INFO_T, once i get that, i need to read the
elements defined in the union or structure.
I have written a code but i am unable to achieve what i wanted.
Can anyone guide me in this?
Thanks and Regards,
Dharshana
You could use Tie::File to treat the file's lines as an array:
use strict;
use warnings;
use Fcntl 'O_RDONLY';
require 'Tie/File.pm';
tie my @file, 'Tie::File', 'anyfile.txt', mode => O_RDONLY
or die("Tie::File failed: $!");
for my $n (0 .. $#file) {
local $\ = "\n";
$_ = $file[$n];
if (/CHANNEL_INFO_T/) {
print $file[$n-2];
print $file[$n-1];
print;
}
}
untie @file;
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