FAQ 3.24 Why don't Perl one-liners work on my DOS/Mac/VMS system?

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3.24: Why don't Perl one-liners work on my DOS/Mac/VMS system?

    The problem is usually that the command interpreters on those systems
    have rather different ideas about quoting than the Unix shells under
    which the one-liners were created. On some systems, you may have to
    change single-quotes to double ones, which you must *NOT* do on Unix or
    Plan9 systems. You might also have to change a single % to a %%.

    For example:

        # Unix (including Mac OS X)
        perl -e 'print "Hello world\n"'

        # DOS, etc.
        perl -e "print \"Hello world\n\""

        # Mac Classic
        print "Hello world\n"
         (then Run "Myscript" or Shift-Command-R)

        # MPW
        perl -e 'print "Hello world\n"'

        # VMS
        perl -e "print ""Hello world\n"""

    The problem is that none of these examples are reliable: they depend on
    the command interpreter. Under Unix, the first two often work. Under
    DOS, it's entirely possible that neither works. If 4DOS was the command
    shell, you'd probably have better luck like this:

      perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""

    Under the Mac, it depends which environment you are using. The MacPerl
    shell, or MPW, is much like Unix shells in its support for several
    quoting variants, except that it makes free use of the Mac's non-ASCII
    characters as control characters.

    Using qq(), q(), and qx(), instead of "double quotes", 'single quotes',
    and `backticks`, may make one-liners easier to write.

    There is no general solution to all of this. It is a mess.

    [Some of this answer was contributed by Kenneth Albanowski.]


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