[Perl] Accessing array elements within a sed command in Perl script Post: 302243017

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Top Forums Shell Programming and Scripting [Perl] Accessing array elements within a sed command in Perl script Post 302243017 by SFNYC on Friday 3rd of October 2008 12:05:25 PM

10-03-2008

Registered User

Like otheus said, why use sed in a Perl script? If you are going to use Perl, you had better learn how to use it properly. Otherwise stick with sed.

Here's a small Perl script that will do what you want and create a backup file to boot.

I called this replace.pl

Code:

#!/usr/bin/perl

use strict;
use warnings;
use English qw( -no_match_vars );

my $old;
my $new;
my $oldFH;
my $newFH;
my $dirDH;

my $dir = ".";  #Use current directory

opendir($dirDH, $dir) or die "Cannot opendir $dir\n";

my @test = readdir($dirDH);

foreach $old (@test) {
    next if $old eq '.';  #skip directory entries
    next if $old eq '..';

    $new = "$old.temp";
    open($oldFH, "<", $old)        or die "can't open $old: $OS_ERROR\n";
    open($newFH, ">", $new)        or die "can't open $new: $OS_ERROR\n";
    while (<$oldFH>) {
        $_ =~ s/BIOGRF  321/BIOGRF  332/g;
        print $newFH $_            or die "can't write $new: $OS_ERROR\n";
    }

    close($oldFH)                  or die "can't close $old: $OS_ERROR\n";
    close($newFH)                  or die "can't close $new: $OS_ERROR\n";
    rename($old, "$old.orig")      or die "can't rename $old to $old.orig: $OS_ERROR\n";
    rename($new, $old)             or die "can't rename $new to $old: $OS_ERROR\n";

}

closedir($dirDH) or die "Cannot closedir $dir\n";

exit 0;

Output:

Code:

$ ls -1
test1
test2
test3
test4

$ cat test1 test2 test3 test4
BIOGRF  321
BIOGRF  421
BIOGRF  32X
BIOGRF  199

$ replace.pl

$ cat test1 test2 test3 test4
BIOGRF  332
BIOGRF  421
BIOGRF  32X
BIOGRF  199


$ ls -1
test1
test1.orig
test2
test2.orig
test3
test3.orig
test4
test4.orig

The guts of the code comes from The Perl Cookbook. I just wrapped it around a loop that takes all the files from the current directory and performs your replace command. In your case you just need the while loop that walks through your array called @test.

SFNYC

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LEARN ABOUT PHP

opendir

OPENDIR(3)								 1								OPENDIR(3)

opendir - Open directory handle

SYNOPSIS

       resource opendir (string  $path, [resource  $context])

DESCRIPTION

	Opens up a directory handle to be used in subsequent closedir(3), readdir(3), and rewinddir(3) calls.

PARAMETERS

	      o $path
		- The directory path that is to be opened

	      o $context
		- For a description of the $context parameter, refer to the streams section of the manual.

RETURN VALUES

	Returns a directory handle resource on success, or FALSE on failure.

	If  $path  is  not  a  valid  directory or the directory can not be opened due to permission restrictions or filesystem errors, opendir(3)
       returns FALSE and generates a PHP error of level  E_WARNING. You can suppress the error output of opendir(3) by prepending '@' to the front
       of the function name.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.0.0	|						    |
       |	|						    |
       |	|      $path supports the ftp:// URL wrapper.	    |
       |	|						    |
       | 4.3.0	|						    |
       |	|						    |
       |	| $path  can  also be any URL which supports direc- |
       |	| tory listing, however only the file:// URL  wrap- |
       |	| per supports this in PHP 4			    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES

       Example #1

	      opendir(3) example

	      <?php
	      $dir = "/etc/php5/";

	      // Open a known directory, and proceed to read its contents
	      if (is_dir($dir)) {
		  if ($dh = opendir($dir)) {
		      while (($file = readdir($dh)) !== false) {
			  echo "filename: $file : filetype: " . filetype($dir . $file) . "
";
		      }
		      closedir($dh);
		  }
	      }
	      ?>

	      The above example will output something similar to:

	      filename: . : filetype: dir
	      filename: .. : filetype: dir
	      filename: apache : filetype: dir
	      filename: cgi : filetype: dir
	      filename: cli : filetype: dir

SEE ALSO

       is_dir(3), readdir(3), dir(3).

PHP Documentation Group 														OPENDIR(3)

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