Index for Section 1

Alphabetical listing for U

Bottom of page

units(1)
NAME
  units - Converts units from one measure to another

SYNOPSIS
  units [-] [file]

DESCRIPTION
  The units command converts quantities expressed in one measurement to their
  equivalents in another.  The units command is an interactive command.	 It
  prompts you for the unit you want to convert from and the unit you want to
  convert to.  The units command does multiplicative scale changes only.
  That is, units can convert from one value to another only when the
  conversion is done with a multiplication factor.  For example, units cannot
  convert between degrees Fahrenheit and degrees Celsius because the value of
  32 must be added or subtracted in the conversion.

  You can specify a quantity as a multiplicative combination of units,
  optionally preceded by a numeric multiplier.

  Indicate powers by entering suffixed positive integers and indicate
  division with a / (slash).

  The units command recognizes lb as a unit of mass, but considers pound to
  be the British pound sterling.   Compound names are run together (for
  example, lightyear).	Prefix British units differing from their American
  counterparts with br (for example, brgallon).	 The /usr/share/lib/units
  file contains a complete list of the units that the units command uses.

  Most familiar units, abbreviations, and metric prefixes are recognized by
  the units command, together with the following:

  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 head per unit height of water.

  au	  Astronomical unit.

  The - argument causes units to display a list of all known units and their
  conversion values.  The file argument specifies an alternative units file
  to be used instead of the default file units.

EXAMPLES
  To start the units command, enter:

       units

  Now you can try the following examples.

   1.  To display conversion factors, enter:
	    you have: in
	    you want: cm

	    * 2.540000e+00
	    / 3.937008e-01

       The output from the units command tells you to multiply the number of
       inches by 2.540000e+00 to get centimeters, and to multiply the number
       of centimeters by 3.937008e-01 to get inches.

       These numbers are in standard exponential notation, so 3.937008e-01
       means 3.937008 x 10-1, which is the same as 0.3937008.  The second
       number is always the reciprocal of the first; for example, 2.54 equals
       1/0.3937008.

   2.  To convert a measurement to different units, enter:
	    you have: 5 years
	    you want: microsec

	    * 1.577846e+14
	    / 6.337753e-15

       The output shows that 5 years equals 1.577846 x 1014 microseconds, and
       that 1 microsecond equals 6.337753 x 10-15 years.

   3.  To give fractions in measurements, enter:
	    you have: 1|3 mi
	    you want: km

	    * 5.364480e-01
	    / 1.864114e+00

       The | (vertical bar) indicates division, so 1|3 means one-third. This
       shows that one-third mile is the same as 0.536448 kilometers.

   4.  To include exponents in measurements, enter:
	    you have: 1.2-5 gal
	    you want: floz

	    * 1.536000e-03
	    / 6.510417e+02

       The expression 1.2-5 gal is the equivalent of 1.2 x 10-5.  Do not type
       an e before the exponent.  This example shows that 1.2 x 10-5
       (0.000012) gallons equal 1.536 x 10-3 (0.001536) fluid ounces.

   5.  To specify complex units, enter:
	    you have: gram centimeter/second2
	    you want: kg-m/sec2

	    * 1.000000e-05
	    / 1.000000e+05

       The units gram centimeter/second2 mean "grams x centimeters/second2."
       Similarly, kg-m/sec2 means "kilograms x meters/sec2," which is often
       read as "kilogram-meters per seconds squared".

   6.  If the units you specify after you have and you want are incompatible,
       enter:
	    you have: ft
	    you want: lb

	    conformability
	    3.048000e-01 m
	    4.535924e-01 kg

       The message conformability means the units you specified cannot be
       converted.  Feet measure length, and pounds measure mass, so
       converting from one to the other does not make sense.  Therefore, the
       units command displays the equivalent of each value in standard units.

       In other words, this example shows that 1 foot equals 0.3048 meters
       and that 1 pound equals 0.4535924 kilograms. The units command shows
       the equivalents in meters and kilograms because the command considers
       these units to be standard measures of length and mass.

       Entering <Ctrl-d> causes you to exit from the units program.

FILES
  /usr/share/lib/units
      Contains units and their conversion values.

Index for Section 1

Alphabetical listing for U

Top of page