Robert Elz writes:
The issue which is not so clear is whether the '-' that introduces options
on unix commands, and is used various other places (like scan last:-10)
is really intended to be a hyphen, a minus, or some other kind of dash.
The one on the scan example given is most likely a minus, but in "ls -l"
(or "scan -width") it might really be an "n dash" that is intended (a
minus would appear a little too high to look good.)
This isn't helped by the fact that some people read out "ls -l" as
"ell ess dash ell" and others as "ell ess minus ell" (I don't recall
ever hearing "ell ess hyphen ell" but someone has probably said that.)
No-one has ever been too concerned about this, as when we type (in ascii)
there is but one character to use for all purposes (other than that sometimes
we use it twice to simulate an "m dash",) but when typesetting, it makes
a difference.
It is also a problem when copy/paste gets involved (as often happens
in manpages). The historical convention has been to use \- for flags.
This gets transformed into an actual minus (Unicode U+2212) in some
typeset outputs, like Postscript and PDF and even HTML, but this
varies widely across troff implementations, to say the least.
Of course back in the 1970s nobody imagined using a mouse to select
typeset text and paste it into a terminal. The historical decisions
from back then thus negatively affect the modern, rich-fonted,
Unicode-oriented world.
Personally I like the route taken by troff's -mdoc macros: flags are
prefixed with ASCII '-' (so copy/paste works in all output formats), but
the flags are typeset in a fixed-width font and as a result the '-'
doesn't look unnaturally small.
I have no idea if there is an established convention used by the unix
book publishing industry.
At least all of Kernighan's books (such as UPE) use \- for command-line
flags.
--
Anthony J. Bentley
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