CODEWITHSUNDEEP
regexlinuxbashcommand-linegrep
DocWiki
DocWiki

Reputation: 3584

Simple Grep Mismatch problem

I am using Ubuntu 10.10 and using Grep to process some HTML files.

Here is the HTML snippet:

<a href="video.php?video=one-hd.mov"><img src="/1.jpg"><a href="video.php?video=normal.mov"><img src="/2.jpg"><a href="video.php?video=another-hd.mov">

I would like to extract one-hd.mov and another-hd.mov but ignore normal.mov.

Here is my code:

example='<a href="video.php?video=one-hd.mov"><img src="/1.jpg"><a href="video.php?video=normal.mov"><img src="/2.jpg"><a href="video.php?video=another-hd.mov">'
echo $example | grep -Po '(?<=video.php\?video=).*?(?=-hd.mov">)'

The result is:

one
normal.mov"><img src="/2.jpg"><a href="video.php?video=another

But I want 

one
another

There is a mismatch there.

Is this because of the so-called Greedy Regular Expression?

I am sing GREP but any command line bash tools are welcome to solve this problem like sed etc.

Thanks a lot.

Upvotes: 1

Views: 1133

Answers (3)

Fredrik Pihl
Fredrik Pihl

Reputation: 45670

Solution using awk:

{
    for(i=1;i<NF;i++) {
        if ($i ~ /mov/) {
            if ($i !~ /normal/){
                sub(/^.*=/, "", $i)
                print $i
            }
        }
    }
}

outputs:

$ awk -F'"' -f h.awk html
one-hd.mov
another-hd.mov

But I strongly advice you to use a html-parser for this instead, something like BeautifulSoup

Upvotes: 1

yankee
yankee

Reputation: 40850

Here is a solution using xmlstarlet:

$ example='<a href="video.php?video=one-hd.mov"><img src="/1.jpg"><a href="video.php?video=normal.mov"><img src="/2.jpg"><a href="video.php?video=another-hd.mov">'
$ echo $example | xmlstarlet fo -R 2>/dev/null | xmlstarlet sel -t -m "//*[substring(@href, string-length(@href) - 6, 7) = '-hd.mov']" -v 'substring(@href,17, string-length(@href) - 17 - 3)' -n
one-hd
another-hd

$

Upvotes: 1

clt60
clt60

Reputation: 63972

You want use Perl regexes for grep - why not directly perl?

echo "$example" | perl -nle 'm/.*?video.php\?video=([^"]+)">.*video.php\?video=([^"]+)".*/; print "=$1=$2="'

will print

=one-hd.mov=another-hd.mov=

Upvotes: 2

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