perl -- executes perl
-i   -- in-place editing
-n   -- implict loop
-w   -- turn on warnings (why?)
-e   -- execute the following string as the program

print    -- print what is in $_ (only executed if the unless is  false)
unless   -- execute the previous command if the result of the following
            expression is 0, undef, or '' (or the equivalent)
32 .. 32 -- construct a list containing the numbers 32 through 32
filename -- the file to edit

You don't understand context. An expression in scalar context doesn't mean it's evaluated in list context, and then the list is evaluated in scalar context.

No, it means the expression is evaluated in scalar context. And .. doesn't act at all the same in scalar context as in list context. From the manual page:

       In scalar context, ".." returns a boolean value.  The
       operator is bistable, like a flip-flop, and emulates the
       line-range (comma) operator of sed, awk, and various edi-
       tors.  Each ".." operator maintains its own boolean state.
       It is false as long as its left operand is false.  Once
       the left operand is true, the range operator stays true
       until the right operand is true, AFTER which the range
       operator becomes false again.  It doesn't become false
       till the next time the range operator is evaluated.  It
       can test the right operand and become false on the same
       evaluation it became true (as in awk), but it still
       returns true once.  If you don't want it to test the right
       operand till the next evaluation, as in sed, just use
       three dots ("...") instead of two.  In all other regards,
       "..." behaves just like ".." does.

       The right operand is not evaluated while the operator is
       in the "false" state, and the left operand is not evalu-
       ated while the operator is in the "true" state.  The
       precedence is a little lower than || and &&.  The value
       returned is either the empty string for false, or a
       sequence number (beginning with 1) for true.  The sequence
       number is reset for each range encountered.  The final
       sequence number in a range has the string "E0" appended to
       it, which doesn't affect its numeric value, but gives you
       something to search for if you want to exclude the end-
       point.  You can exclude the beginning point by waiting for
       the sequence number to be greater than 1.  If either
       operand of scalar ".." is a constant expression, that
       operand is implicitly compared to the $. variable, the
       current line number.  Examples:

       As a scalar operator:

           if (101 .. 200) { print; }  # print 2nd hundred lines
           next line if (1 .. /^$/);   # skip header lines
           s/^/> / if (/^$/ .. eof()); # quote body
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Abigail

I've read those paragraphs at least a dozen times since I first saw reference to the "flip-flop operator" in the spoiler for an obfu, one of erudil's or maybe on of yours, and I still have trouble applying it.

If anyone has a less wordy, more .. um .. transparent description of the .. and ... in a scalar context, or even better a simple example of use that is self-contained and demonstrative, I for one would find that very useful.

---

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