Multiline Search-Replace With Perl One-liner

**cibalo** · 01-12-2012

Hello,

I have migrated my free website to my linux web server recently. I have to re-code all my htm files, of which they were created under Windows.

I need to make a search and replace with Perl One-liner. I want to search/replace backward slash to forward slash only in the relative image path for all <img> tags, which may span over multiple lines.
So the <img> tag may like this:
<html>
<body>
<img src="public_html\images\Buster.jpg" height="250" width="128"
alt=" /\ See above"
title=" /\
See above" />
</body>
</html>

Sadly I haven't done RegEx searching in a while now. I'd be very thankful for some help.

Thank you very much in advance!!!

Best Regards,
cibalo

**atreyu** · 01-13-2012

How about a 56-liner?

Code:

#!/usr/bin/perl
use strict;
use warnings;
use File::Copy;

# get files from command line arguments
die "Give me files!\n" unless($#ARGV >= 0);
my(@files) = (@ARGV);

# loop thru list of files
for my $file(@files){

  # make sure file exists
  die $file,": No such file\n" unless(-f$file);

  # temporary copy of file, containing changes
  my $tmpFile = $file.'.tmp';

  # remove the temp file, if it exists
  unlink($tmpFile) if(-f$tmpFile);

  # open a new temp file
  open(TMP,'>',$tmpFile) or die "can't open '$tmpFile': $!\n";

  # read the input file
  open(FH,'<',$file) or die "can't read '$file': $!\n";
  while(<FH>){
    chomp;

    # match on the img tag opening and closing
    if(/<img[ \t]+/ .. /[ \t]+\/>/){

      # match on the portion of the line containing src=""
      if(/(^.*[ \t]+src=")(.*)(".*)$/){
        my $pre = $1;
        my $src = $2;
        my $post = $3;

        # here we swap '\' for '/'
        $src =~ s/\\/\//g;

        print TMP $pre,$src,$post,"\n";
      }else{
        print TMP $_,"\n";
      }
    }else{
      print TMP $_,"\n";
    }
  }
  close(FH);
  close(TMP);

  # if satisifed, write the temp file to original file
#  move($tmpFile,$file);

}

Copy it to a script, call it whatever ("foo.pl"), and make it executable:

Code:

chmod +x foo.pl

Then run it and pass it your HTML files as arguments, e.g.:

Code:

./foo.pl $(find . -type f -iname '*.html')

But really, first just try it on one test file first, e.g.:

Code:

./foo.pl test.html

It will create a temporary file for each input file, containing the actual changes (e.g., "test.html.tmp"). Look at this resultant file. If it looks okay, then remove the comment character (#) from line 54 (or thereabouts - the one that says move($tmpFile,$file); ) to allow the script, going forward, to move the temp file into place, overwriting the original file.

**cibalo** · 01-14-2012

Originally Posted by atreyu

How about a 56-liner?

Hello atreyu,

Thank you very much for replying to my post. What I need is a working solution, be it a 56-liner or one-liner. I do try your suggestions and it works like a charm.

For testing, I even change the order of attributes ("alt" and "src") in img tag as:
<html>
<body>
<img height="250" width="128" alt=" /\ See above"
src="public_html\images\Buster.jpg"
title=" /\
See above" />
</body>
</html>

Then run it:
$ ./foo.pl perltest.html
$ ls perltest.html*
perltest.html perltest.html.tmp
$ diff -s perltest.html*
4c4
< src="public_html\images\Buster.jpg"
---
> src="public_html/images/Buster.jpg"

Best Regards,
cibalo

**atreyu** · 01-14-2012

sweet - i'm glad it works. any chance to sling some perl code...

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