Problem with appending files

ravi45722 has asked for the wisdom of the Perl Monks concerning the following question:

I am trying to append a file with some text. But some times it starts with new line. Some times the new is not appearing. So, I tried in so many ways. I am tied here.

#!/usr/bin/perl

use warnings;
use strict;

open (FD,">>text.txt");

my $flag = 0;

foreach my $num (0 .. 10)
{
        if ($flag == 1)
        {
                print FD $/,$num;
        }
        if ($flag ==0)
        {
                print FD $num;
                $flag = 1;
        }
}
[download]

Expect Output :

 Its old text 
0
1
2
3
4
5
6
7
8
9
10
[download]

Its working some times and not working some times. Why its happening????

Comment on Problem with appending files Select or Download Code

Replies are listed 'Best First'.
Re: Problem with appending files by Corion (Patriarch) on Jan 21, 2016 at 13:13 UTC
What is the output when it is working? Have you made sure that the problem is related to appending to a file? Does your script output the expected output when it is writing to `STDOUT` instead of appending to a file?	[reply] [d/l]
Re^2: Problem with appending files by ravi45722 (Pilgrim) on Jan 21, 2016 at 13:31 UTC
in my actual code `open (FD,">>OTAPA_Errors"); foreach my $num (@errors) { if ($flag == 1) { print FD $/,$num; } if ($flag ==0) { print FD $num; $flag = 1; } }` [download] If I run this sometimes a new line is added at the starting. So i removed new line by using flag. But some times the new line missing.	[reply] [d/l]
Re^3: Problem with appending files by choroba (Cardinal) on Jan 21, 2016 at 14:00 UTC
Is the code inside a loop? Do you reset the flag for the next open of the file? If it's a global variable, you need to reset it to 0, as it keeps the old value. It's better to use strict and scope the flag properly. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l]
Re^3: Problem with appending files by hdb (Monsignor) on Jan 21, 2016 at 13:47 UTC
May be the newline is already in the file you are appending to, only sometimes. Adding a newline accidentially is easy when inspecting a file with some editors under some OSes.	[reply]
Re^4: Problem with appending files by ravi45722 (Pilgrim) on Jan 21, 2016 at 14:12 UTC
Re^3: Problem with appending files by Corion (Patriarch) on Jan 21, 2016 at 13:33 UTC
Maybe something sets or resets `$/`. ~~Note that your code never can go into the `if( $flag == 0 )` branch with the code as you show it.~~ Maybe you want to add some debugging statements using `warn`. Your code can only one get into the `$flag==0` branch. I can only recommend reducing your code so that you produce a small, self-contained program (20 lines or so) that still has the problematic behaviour.	[reply] [d/l] [select]