from
The Free On-line Dictionary of Computing (8 July 2008)
command line option
option
<software> (Or "option", "flag", "switch", "option switch") An
argument to a command that modifies its function rather than
providing data. Options generally start with "-" in {Unix} or
"/" in {MS-DOS}. This is usually followed by a single letter
or occasionally a digit. More recently, {GNU} software
adopted the --longoptionname style, usually in addition to
traditional, single-character, -x style equivalents.
Some commands require each option to be a separate argument,
introduced by a new "-" or "/", others allow multiple option
letters to be concatenated into a single argument with a
single "-" or "/", e.g. "ls -al". A few Unix commands
(e.g. {ar}, {tar}) allow the "-" to be omitted. Some options
may or must be followed by a value, e.g. "cc prog.c -o prog",
sometimes with and sometimes without an intervening space.
{getopt} and {getopts} are commands for parsing command line
options. There is also a {C} library routine called getopt
for the same purpose.
(2007-02-18)