Today I came upon a quirk (bug?) of shebang/hash-bang line argument parsing. Past experience (and perlrun) tells me that perl (lowercase) parses commandline options from the shebang line:

$ cat test-none.pl
#!/usr/bin/perl
print "foo";

$ cat test-ell.pl
#!/usr/bin/perl -l
print "foo";

$ perl -l test-none.pl
foo

$ perl test-ell.pl
foo

$ ./test-ell.pl
foo

$ ./test-none.pl
foo$ # note the lack of a newline

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So, why do I get the wide-character warning in the following:

$ cat test-noCDS.pl
#!/usr/bin/perl -l
print "\x{101}";

$ cat test-withCDS.pl
#!/usr/bin/perl -l -CDS
print "\x{101}";

$ perl -l -CDS -e 'print "\x{101}"'
Ä

$ perl -CDS test-noCDS.pl
Ä

$ perl test-withCDS.pl
Wide character in print at test-withCDS.pl line 2.
Ä

$ ./test-withCDS.pl
Ä

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Even more mysteriously, it seems the -CDS is getting applied (as seen by testing ${^UNICODE}), but not to STDOUT:

$ cat CDS.pl
#!/usr/bin/perl -l -CDS
print ${^UNICODE}, ' ', "\x{101}"

$ perl CDS.pl
Wide character in print at CDS.pl line 2.
31 Ä

$ perl -CDS CDS.pl
31 Ä

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Is this a bug? If so, is it merely a documentation bug? (need a warning that -C doesn't get applied in time to affect STD(IN|OUT|ERR) if it's in a shebang?)

$ perl -v
This is perl, v5.8.8 built for i686-linux

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In reply to Bug in perl -C (Unicode) option parsing? by benizi

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