Re: STDIN Odd Bevahior in Linux Environments

[liverpole]

Hi bichonfrise74,

I've not seen that before, but if you try running the script utility (which spawns a new shell, and then records all I/O until you exit the shell, saving it to a specified textfile, or typescript by default), it might give you more clues about what's happening.

For example:

[liverpole@myhost ~]% cat example.pl
#!/usr/bin/perl -w

use strict;

print "Enter: ";
my $input = <STDIN>;

[liverpole@myhost ~]% script output
Script started, file is output
liverpole@myhost# ./example.pl
Enter: tes
liverpole@myhost# exit
exit
Script done, file is output
[liverpole@myhost ~]% cat output
Script started on Wed Sep 23 17:46:45 2009
liverpole@myhost# ./example.pl
Enter: tes
liverpole@myhost# exit
exit

Script done on Wed Sep 23 17:47:08 2009

In the above example, the backspace key worked as expected, which you can see very clearly when you edit the script file "output", as the line with the backspace is revealed to be:

Enter: test^H ^H^M

Clearly it's doing a backspace, followed by a space (to erase the final 't' of 'text'), followed by another backspace.

[bichonfrise74]

This is what I see when I do cat output...

Script started on Wed 23 Sep 2009 03:20:17 PM PDT
home:~$ perl 33.pl
Enter: test^H^Hhello^H^Hm^H
home:~$ exit
exit

Script done on Wed 23 Sep 2009 03:20:29 PM PDT

This is what I see when I run vi output...

Script started on Wed 23 Sep 2009 03:20:17 PM PDT
^[]0;home: ~^Ghome:~$ perl 33.pl^M
Enter: test^H^Hhello^H^Hm^H^M
^[]0;home: ~^Ghome:~$ exit^M
exit^M
Script done on Wed 23 Sep 2009 03:20:29 PM PDT

It looks like only ^M (enter key) is working properly and ^H is not. Hmm... does this mean that this is not a Perl-related problem?