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inserting a string to a text file

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# 1  
Old 05-21-2009
inserting a string to a text file
Hello

Can somebody please help me with the following script?
I'm trying to create a text file with 20 blank lines and then insert a string in line 2 but nothing is printed in the itxtfile. I can create the file with 20 blank lines but when I "tell" it to print something on the second line, it doesn't work.
Can somebody please tell me what am I doing wrong?

Thanks a lot

Code:
system ("touch /home/yanni/scripts/intxtfile"); 
my ($fileread, $filein, $fileout);
$filein = '/home/yanni/scripts/intxtfile';
$fileout = 'file.tmp';


open $fileread, '>', $filein || die ("Can't open: $filein $!");
print $fileread "\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n"; 
close $fileread;

 open ($fileread, '<', $filein)  || die "Can't open: $filein $!";
 open ($filewrite,'>', $fileout) || die "Can't open: $fileout $!";
 
 while (<$fileread>) {
                      print $filewrite $_;
                      if ($.==2) { print $fileread "blablabla";}

                             }              

close ($fileread);
close ($filein);
close ($fileout);
rename ($fileout, $filein) || die "Unable to rename: $!";

# 2  
Old 05-21-2009
don't understand what you are doing. If you want to insert something on second line, then do it while you are creating the blank lines. also, there is no need to call system() to touch a file. Perl has its own touch. see perldoc -f touch
# 3  
Old 05-21-2009
I agree with ghostdog, your script seems to be poorly written and your requirements are vague, but maybe that is because you lack perl experience. But one problem is clearly evident and you should see it assuming you wrote the code you posted:

Code:
if ($.==2) { print $fileread "blablabla";}

In the above line you are trying to print to $fileread, which is a file opened for reading, not writing.
# 4  
Old 05-21-2009
Quote:
Originally Posted by goude
...I'm trying to create a text file with 20 blank lines and then insert a string in line 2 but nothing is printed in the itxtfile. I can create the file with 20 blank lines but when I "tell" it to print something on the second line, it doesn't work.
...
Not sure about your code, but is this what you are looking for ?

Code:
$
$ perl -e '{open(OUT,">file.tmp"); print OUT "\nBLABLABLA\n"."\n"x18; close(OUT)}'
$
$ cat -n file.tmp
     1
     2  BLABLABLA
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
$
$

tyler_durden
# 5  
Old 05-22-2009
Thank you all for your replies

To KevinADC: I don't understand why you said "the file is opened for reading not for writing". I thought the ">" symbol means write to file, isn't it?. You confused me there.

Code:
 open ($fileread, '<', $filein)  || die "Can't open: $filein $!"; 
 open ($filewrite,'>', $fileout) || die "Can't open: $fileout $!";

To Tyler: Your perl line is brilliant. That's exactly what I'm looking for but I'd rather do that in a Perl script. I'm long way from writing Perl liners. Smilie
Last edited by goude; 05-22-2009 at 05:52 AM..
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