Are you writing your programs on Windows and copying it "as is" (say, by using binary FTP, HTTP PUT, HTTP file upload, scp, copying on a mounted disk, sneakernet, or something else) to a Unix machine?

In that case, all the lines will have a trailing ^M (before the newline). Without the -w, you're telling the kernel you want to execute "/usr/bin/perl^M". That's a perfectly valid filename under Unix, but it's unlikely such a program exists.

With the -w, the line ends with "-w^M", and perl itself can deal with the Windows ending.

The solution is to strip the ^M's out of your file. FTP ASCII upload will do this automatically for you. Or use a utility like dos2unix, or something like: 

perl -wple 's/^M//' yourfile

[download]
on the Unix side.

Abigail

In reply to Re: Why do I need -w in a cgi script by Abigail-II
in thread Why do I need -w in a cgi script by Anonymous Monk

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