UNIX for Dummies Questions & Answers

Thanks Bartus ... your explanation was clear ... actually the $/ variable you have already described in another post so its fine ... Could you remind me again the $& variable please? I guess I can find it on perlvar too, but in this context will be nice to hear from you.
Related to this question what if instead of replacing the characters I had to insert or delete the position_file letters in the original file ?? What could be changed in the code to do that ?? I'm imagining a push/pop function somewhere but could you enlighten me on this when you have a few moments?
Cheers and thanks for all your help always.
Hv a nice day

$& holds string that was matched by last regex, so in s/.{100}/$&\n/g; it will contain hundred characters, to which newline is then appended. It is done to restore your formating of hundred chars per line. As for the changes in behavior of the script, to delete characters on positions stored in "position file", substitute

Code:

$F[$i-1]=$h{$i}

with

Code:

$F[$i-1]=""

To insert characters at specified positions, substitute the same line with:

Code:

$F[$i-2].=$h{$i}

Thanks a lot Bartus
Hv a nice day and a good weekend ahead
Cheers !!