units - Converts units from one measure to another
units [-] [file]
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 conver-
sion is done with a multiplication factor. For example, units cannot con-
vert 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 divi-
sion 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 exam-
ple, lightyear). Prefix British units differing from their American coun-
terparts 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.
To start the units command, enter:
Now you can try the following examples.
1. To display conversion factors, enter:
you have: in
you want: cm
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
2. To convert a measurement to different units, enter:
you have: 5 years
you want: microsec
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
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
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
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,
you have: ft
you want: lb
The message conformability means the units you specified cannot be
converted. Feet measure length, and pounds measure mass, so convert-
ing 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.
Contains units and their conversion values.