Dear Monks

To my understanding "+<" will not clobber the contents of file when you try to write sth to it.

but...

   #!/usr/bin/perl -w
   use strict;
   
   open (F, "+<",$ARGV[0]);
   my $out = "";
   while(<F>){
       chomp;
       $out .= $_."\tadd sth\n" if($.%2 == 0);
   }
  seek(F,0,0);
  print F $out;
  close(F);

[download]

I was expecting to insert the $out contents at the beginning of the file.

But it just removes the old contents of the file and prints the $out contents instead.

Does anyone have insight on this? Thank you!

In reply to questions regarding "+<" by lightoverhead

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