Gossamer Forum: General: Perl Programming: edit a word in a flat file

Oct 25, 2002, 2:27 AM

wired_lain

Novice (18 posts)

Oct 25, 2002, 2:27 AM

Post #1 of 7

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edit a word in a flat file

Im having problems figuring out this.

I have a flat file that has a list and each line goes like this:

number/user/name/type/thing/place

what if I just want to edit the value of thing? I can read the file and check against it but I cant figure out a way to just edit one value

I cant seem to thiink of a way to do that

thanks

lain

Oct 26, 2002, 11:38 AM

Andy

Veteran / Moderator (18441 posts)

Oct 26, 2002, 11:38 AM

Post #2 of 7

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Re: [wired_lain] edit a word in a flat file In reply to

Its no where near as easy as with SQL, but here is an example bit of code (there IS better out there... Wink

)

Code:
my $find = "something"; # the word you want to replace... 

open(FILE, "/path/to/file/readig.txt") || die "Cant  
open(NEWFILE, "/path/to/file/to/write-to.txt") || die "Cant open. Reason: $!"; 

  while (<FILE>) { 

      chomp; 
      my ($number,$user,$name,$type,$thing,$place) = split("/",$_); 

   if ($thing eq $find) { 

     print NEWFILE "/$number/$user/$name/$type/$find/$place\n"; 

   } else { 

    print NEWFILE $_ . "\n"; 

   } 

  } 

close(FILE); 
close(NEWFILE);

This code is UNTESTED, I just quickly wrote it before going out clubbing Wink

Enjoy :)

Andy (mod)
andy@ultranerds.co.uk

Oct 27, 2002, 10:09 PM

wired_lain

Novice (18 posts)

Oct 27, 2002, 10:09 PM

Post #3 of 7

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Re: [Andy] edit a word in a flat file In reply to

Thanks Andy, you were a big help, heres what I came up with

sub edit_pass{
open (PASS, "<$pwd") or &cgierr ("unable to open: user.db.\nReason: $!");
@lines = <PASS>;
@lines = split(/\n/);
close PASS;

open (PASS, ">docno.log") || die "CANT";
foreach $line (@lines) {
chomp;
my ($user_no, $name_jap, $name_eng, $loginname, $passwd, $root) = split(/::/, $line);
$root =~ s/[^0-9a-z\/]//gi;
# if ($passwd eq $oldpass){
if ($line =~ /^$oldpass::/) {
my $newline .= join("::", $user_no, $name_jap, $name_eng, $loginname, $newpass1, $root);
print PASS "$newline\n";
}
else {
print PASS $line . "\n";
}}
close (PASS);
}

changing the distinct part of the line is now working but the problem is I end up with deleting all the other items in the document except for the line that I changed. I cant figure out whats wrong. thanks so much

Lain

Last edited by:

wired_lain: Oct 27, 2002, 10:39 PM

Oct 28, 2002, 12:22 AM

Andy

Veteran / Moderator (18441 posts)

Oct 28, 2002, 12:22 AM

Post #4 of 7

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Re: [wired_lain] edit a word in a flat file In reply to

open (PASS, ">docno.log") || die "CANT";

to

open (PASS, ">>docno.log") || die "CANT";

Andy (mod)
andy@ultranerds.co.uk

Oct 28, 2002, 12:27 AM

wired_lain

Novice (18 posts)

Oct 28, 2002, 12:27 AM

Post #5 of 7

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Re: [Andy] edit a word in a flat file In reply to

If I do that then isnt the line that I am suppose to edit not going to be erased? the other lines are saved but so is the one I am editing, is there any way to go around this?

Oct 28, 2002, 3:07 AM

Andy

Veteran / Moderator (18441 posts)

Oct 28, 2002, 3:07 AM

Post #6 of 7

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Re: [wired_lain] edit a word in a flat file In reply to

Nope...

>> is to add something to a file
> is to overwrite the old data, and add the new stuff

Wink

Andy (mod)
andy@ultranerds.co.uk

Oct 28, 2002, 9:36 PM

wired_lain

Novice (18 posts)

Oct 28, 2002, 9:36 PM

Post #7 of 7

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Re: [Andy] edit a word in a flat file In reply to

I got the script to work yay!

thanks Andy