Perl, my old scripts run but a I can't run new scripts

Question

I'm getting back into Perl and I have old practices files which will run fine. But when I write a new script nothing happens. Currently using 10.4.5, BBEdit 6.1 Lite. All my scripts have the following first line: #!/usr/bin/perl
Old scripts work, if I type a new one and run it nothing happens except I get a new command line prompt.
On the other hand if I remove the #!/usr/bin/perl line and go to the command line and type: perl programname. Programname will run!?!!?
I still have to dig into the man pages on perlrun. Does anyone have a clue?
Thanks, Dennis

Answer 1

thanks for all the information. I really appreciate the replies.
all of my experience is based on the O'Reilly book I mentioned above. I've tried to respond to all the comments but the order is not exact.
chmod 755 uses an octal argument to change the permissions on the file.
In particular the file becomes executable.
1. which perl returned /usr/bin/perl which explains why the old perl programs run. Perl is where it's supposed to be.
2. I haven't done anything to my system as far as a rehash goes(what is that anyway?)
3. the wc -l command returned 0 hw2, meaning zero lines, bingo!! this must be it, don't you think?
4. So why will BBEdit let me write, save, reopen files with content and UNIX sees the file as empty.
5. when these programs are run, nothing happens I just get a new prompt.
BTW the program, called hw2, in question reads:
#!/usr/bin/perl
print "hello, world. \n";
get this: when I do cat hw2 I get a listing without the #!/usr/bin/perl at the top ie I see one line instead of two even though wc -l reports zero lines, what's up with that???
I think that's everything for now. I'm going to look for another texteditor
ps does it matter what the line end character is? I can choose Mac or UNIX.