Multiline Grep


 
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# 1  
Multiline Grep

How does one do a search for a multiline regular experssion and output the results to a file.

I know this won't work since grep only searches single lines:
Code:
egrep '<a>.*?</a>' source.xml > output.xml


Here are some sample patterns I'd like to match and output to a single file:
Code:
 
<a>..............</a>

<a>
   ..................
</a>


<a>
   ..................
   ..................
   ..................
</a>

Do I need perl for this?

Many Thanks!
-Mark
# 2  
With Unix there is always more than one way to skin a cat. I am not good with regular expressions so I did this with awk:

#!/usr/bin/ksh

cat source.xml | awk 'BEGIN {x=0}
{
if ($0~"<a>") {x=1}
if (x==1) {print $0}
if ($0~"</a>") {x=0}
}' > output.xml
# 3  
try this Perl script:
Code:
#!/usr/local/bin/perl
# multiliner.pl
use strict;
my $filename = shift;
open (FILE, "<", $filename)  or  die "Failed to read file $filename : $! \n";
my $whole_file;
{
    local $/;
    $whole_file = <FILE>;
}
close(FILE);
while ($whole_file =~ m#\<a\>(.*?)\<\/a\>#g) {
    print $1 . "\n";
}

run this script as:
Code:
perl multiliner.pl source.xml  > output.xml

# 4  
Quote:
Originally Posted by Yogesh Sawant
Code:
while ($whole_file =~ m#\<a\>(.*?)\<\/a\>#g) {

I think you may need the s option to span newlines
Code:
while ($whole_file =~ m#\<a\>(.*?)\<\/a\>#sg) {


Last edited by kahuna; 03-14-2008 at 11:36 AM..
# 5  
Thanks for the help!
 

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