From: "Bob McConnell" <r...@cbord.com> It doesn't, the line starts with a '#' so it is ignored. You have to tell MS-Windows to associate .pl files with perl.exe. Then the OS does what #! was supposed to. But it will always use the same copy of perl.exe, so you don't get the ability to use different releases for different scripts.
Bob McConnell Well, not exactly ignored. Here is a sample zzz.pl script: #!/usr/foo/bar -w print "ok"; Normally, if the shebang line would be really ignored, the program should run fine if the program is ran using: perl zzz.pl But the result is: E:\>perl zzz.pl Can't exec /usr/foo/bar at zzz.pl line 1. Here is another sample script: #!/python27/python.exe import sys print(sys.copyright) And here I ran it with Perl: E:\>perl zzz.pl E:\>Copyright (c) 2000-2010 ActiveState Software Inc. Copyright (c) 2001-2010 Python Software Foundation. ... So even though the program is ran using the Perl interpreter, when it finds the shebang line, even under Windows, it executes the program using the interpreter found in that line, no matter it is not even Perl. But this is because Perl is smarter than Python for this thing. Here is a Perl code I put in the file zzz.py: #!/usr/bin/perl use CGI; print $CGI::VERSION; If I run it with Python, see what happends: E:\>python zzz.py File "zzz.py", line 2 use CGI; ^ SyntaxError: invalid syntax So it means that Python doesn't parse the shebang line and run the program with the program from it. Which thing is better? Perl is smarter, but it might be too smart and can create confusion for newbies. For example, the program will give an error if it will have a shebang line with a non-existent path like: #!/foo/bar/baz But it won't give an error when using a shebang like: #!/foo/sperlito/bar and neither when using one like: #!/foo/bar/baz/who/knows/others/perl/ok/zuzu because these paths contain the string "perl" (probably). So a shebang line like #!perl is enough if you want to use those switches. Octavian -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
