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     units -- conversion program


     units [-f filename] [-qv] [from-unit to-unit]


     The following options are available:

     -f filename
	     Specify the name of the units data file to load.

     -q      Suppress prompting of the user for units and the display of sta-
	     tistics about the number of units loaded.

     -v      Print the version number.

     from-unit to-unit
	     Allow a single unit conversion to be done directly from the com-
	     mand line.  The program will not print prompts.  It will print
	     out the result of the single specified conversion.


     The units program converts quantities expressed in various scales to
     their equivalents in other scales.  The units program can only handle
     multiplicative scale changes.  It cannot convert Celsius to Fahrenheit,
     for example.  It works interactively by prompting the user for input:

	 You have: meters
	 You want: feet
		 * 3.2808399
		 / 0.3048

	 You have: cm^3
	 You want: gallons
		 * 0.00026417205
		 / 3785.4118

	 You have: meters/s
	 You want: furlongs/fortnight
		 * 6012.8848
		 / 0.00016630952

	 You have: 1|2 inch
	 You want: cm
		 * 1.27
		 / 0.78740157

     Powers of units can be specified using the '^' character as shown in the
     example, or by simple concatenation: 'cm3' is equivalent to 'cm^3'.  Mul-
     tiplication of units can be specified by using spaces, a dash or an
     asterisk.	Division of units is indicated by the slash ('/').  Note that
     multiplication has a higher precedence than division, so 'm/s/s' is the
     same as 'm/s^2' or 'm/s s'.  Division of numbers must be indicated using
     the vertical bar ('|').  To convert half a meter, you would write '1|2
     meter'.  If you write '1/2 meter' then the units program would interpret
     that as equivalent to '0.5/meter'.  If you enter incompatible unit types,

     The conversion information is read from a units data file.  The default
     file includes definitions for most familiar units, abbreviations and met-
     ric prefixes.  Some constants of nature included are:

	   pi	      ratio of circumference to diameter
	   c	      speed of light
	   e	      charge on an electron
	   g	      acceleration of gravity
	   force      same as g
	   mole       Avogadro's number
	   water      pressure per unit height of water
	   mercury    pressure per unit height of mercury
	   au	      astronomical unit

     The unit 'pound' is a unit of mass.  Compound names are run together so
     'pound force' is a unit of force.	The unit 'ounce' is also a unit of
     mass.  The fluid ounce is 'floz'.	British units that differ from their
     US counterparts are prefixed with 'br', and currency is prefixed with its
     country name: 'belgiumfranc', 'britainpound'.  When searching for a unit,
     if the specified string does not appear exactly as a unit name, then
     units will try to remove a trailing 's' or a trailing 'es' and check
     again for a match.

     To find out what units are available read the standard units file.  If
     you want to add your own units you can supply your own file.  A unit is
     specified on a single line by giving its name and an equivalence.	Be
     careful to define new units in terms of old ones so that a reduction
     leads to the primitive units which are marked with '!' characters.  The
     units program will not detect infinite loops that could be caused by
     careless unit definitions.  Comments in the unit definition file begin
     with a '/' character at the beginning of a line.

     Prefixes are defined in the same was as standard units, but with a trail-
     ing dash at the end of the prefix name.  If a unit is not found even
     after removing trailing 's' or 'es', then it will be checked against the
     list of prefixes.	Prefixes will be removed until a legal base unit is

     Here is an example of a short units file that defines some basic units.

	   m	     !a!
	   sec	     !b!
	   micro-    1e-6
	   minute    60 sec
	   hour      60 min
	   inch      0.0254 m
	   ft	     12 inches
	   mile      5280 ft


     The effect of including a '/' in a prefix is surprising.

     Exponents entered by the user can be only one digit.  You can work around
     this by multiplying several terms.

     The user must use | to indicate division of numbers and / to indicate
     division of symbols.  This distinction should not be necessary.
     /usr/share/misc/units.lib	the standard units library


     Adrian Mariano <adrian@cam.cornell.edu>

FreeBSD 5.4			 July 14, 1993			   FreeBSD 5.4


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