$ cat -e cM.pl
#!/usr/bin/perl^M$
^M$
print "Hello, World!";^M$

$ ./cM.pl
: bad interpreter: No such file or directory

$ cat -e cM--.pl
#!/usr/bin/perl --^M$
^M$
print "Hello, World!";^M$

$ ./cM--.pl
Hello, World!