Use grep to extract the value from the file

Question

I have the file with the following content:

<rdf:RDF
    xmlns:rdf="/www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:foaf="/xmlns.com/foaf/0.1/"
    xmlns:jfs="//abc.net/xmlns/prod/xyz/jfs/1.0/">
  <rdf:Description rdf:about="//alm.com/abc/users/piku">
    <foaf:mbox rdf:resource="mailto:[email protected]"/>
    <foaf:nick>piku</foaf:nick>
    <foaf:name>Pallavi Mishra</foaf:name>
    <jfs:archived rdf:datatype="//www.w3.org/2001/XMLSchema#boolean"
    >false</jfs:archived>
    <rdf:type rdf:resource="//xmlns.com/foaf/0.1/Person"/>
  </rdf:Description>
</rdf:RDF>

Hoe can I extract email id '[email protected]' and name 'Pallavi Mishra' from this file using perl or grep.

My piece of code is:

my $Name = `cat abc.json | perl -l -ne '/<j.0:name>(.*)<\\/j.0:name>/ and print \$1'`;
my $EmailAddress = `cat abc.json | grep mailto | awk 'BEGIN{FS="\\"|:"} {for(i=1;i<NF;i++) if(\$i ~ /@/) print \$i}'`;

Answer 1

With xmlstarlet:

For the name:

xmlstarlet sel -t -v /rdf:RDF/rdf:Description/foaf:name file

And for the email address:

xmlstarlet sel -t -v "/rdf:RDF/rdf:Description/foaf:mbox/@rdf:resource" file

You could add to the second one the sed statement to remove the mailto part:

xmlstarlet ... | sed 's/^mailto://g'

Answer 2

You should use a proper XML parser such as XML::LibXML

This short program demonstrates the idea

use strict;
use warnings;
use 5.014;  # For non-destructive substitution

use XML::LibXML;

my $doc = XML::LibXML->load_xml(IO => \*DATA);

my $desc = $doc->find('/rdf:RDF/rdf:Description')->get_node(1);
my $mbox = $desc->find('foaf:mbox/@rdf:resource')->string_value  =~ s/^mailto://ir;
my $name = $desc->find('foaf:name')->string_value;
print qq{"$name" <$mbox>\n};

__DATA__
<rdf:RDF
    xmlns:rdf="/www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns:foaf="/xmlns.com/foaf/0.1/"
    xmlns:jfs="//abc.net/xmlns/prod/xyz/jfs/1.0/">
  <rdf:Description rdf:about="//alm.com/abc/users/piku">
    <foaf:mbox rdf:resource="mailto:[email protected]"/>
    <foaf:nick>piku</foaf:nick>
    <foaf:name>Pallavi Mishra</foaf:name>
    <jfs:archived rdf:datatype="//www.w3.org/2001/XMLSchema#boolean"
    >false</jfs:archived>
    <rdf:type rdf:resource="//xmlns.com/foaf/0.1/Person"/>
  </rdf:Description>
</rdf:RDF>

output

"Pallavi Mishra" <[email protected]>

Answer 3

Do not try to parse XML using your own Perl string processing. That's a nasty unreliable hack.

Perl is a plenty capable language. You don't need to use shell to help Perl parse XML.

use XML::LibXML;
my $foaf = '/xmlns.com/foaf/0.1/';
my $rdf = '/www.w3.org/1999/02/22-rdf-syntax-ns#';

my $doc = XML::LibXML->new->load_xml(location => 'foof.xml');
my $Name = $doc->getElementsByTagNameNS($foaf, 'name')->[0]->textContent;
my $EmailAddress = $doc->getElementsByTagNameNS($foaf, 'mbox')->[0]->getAttributeNS($rdf, 'resource');
$EmailAddress =~ s/^mailto://;