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search and replace a string in text file.

Feb 27, 2004, 1:00 PM
zeshan
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Feb 27, 2004, 1:00 PM
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search and replace a string in text file.
I have a very simple question .... I have a text file and have to replace only one field in the string.

123|Name|Subject|Read|Receipt
124|Name2|Subject2|Read|Receipt
125|Name3|Subject3|Read|Receipt
126|Name4|Subject4|Read|Receipt

I have to first match the first field ID (e.g. 125) and then replace the 'Read' with 'Unread' only for this line in the text file and save it.
any ideas as how to do it. I have tried a couple of methods but I am stuck with it.

Search and Replace (i.e. Regex) is not the question here, I am asking for how to re-write the file once the replacement has been made.

thanks in advance.

Last edited by:

zeshan: Feb 27, 2004, 1:17 PM
Feb 28, 2004, 1:39 AM
Andy
Veteran / Moderator (18441 posts)
Andy's avatar
Feb 28, 2004, 1:39 AM
Post #2 of 2
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Re: [zeshan] search and replace a string in text file. In reply to
Try this;

Code:
#!/usr/bin/perl

use strict;

my $id_to_match = '125';

unlink('file_new.txt'); # get rid of the new version...

open(READIT,"file.txt") || die "Cant read file.txt. Reason: $!";
open(WRITEIT,">>file_new.txt") || die "Cant write file_new.txt. Reason: $!";
while (<READIT>) {

if ($_ =~ /^$id_to_match\|/) {
$_ =~ s/Read/Unread/;
}

print WRITEIT $_; # may need to change to "$_ \n"


}
close(WRITEIT);
close(READIT);

# now the new version should saved to file_new.txt

Hope that helps.

Cheers

Andy (mod)
andy@ultranerds.co.uk
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