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 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: Ratio of circumference to diameter. Speed of
light. Charge on an electron. Acceleration of gravity.
Same as g. Avogadro's number. Pressure head per unit
height of water. 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: units
Now you can try the following examples. 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. 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. 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. 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. 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". 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
Contains units and their conversion values.
[ Back ]