UNITS(1,C) AIX Commands Reference UNITS(1,C)
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units
PURPOSE
Converts units in one measure to equivalent units in another.
SYNTAX
units ---|
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 (see "Examples"). This command only does multiplicative scale
changes. That is, it can convert from one value to another only when the
conversion is done with a multiplication factor. For example, it can not
convert between degrees Fahrenheit and degrees Celsius, because 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 suffixed positive integers and division by / (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 (such as
lightyear). Prefix British units differing from their American counterparts
with br (brgallon for instance). The file /usr/lib/unittab contains a complete
list of the units that the units command uses.
Most familiar units, abbreviations, and metric prefixes are recognized,
together with the following:
pi Ratio of circumference to diameter
c Speed of light
e Charge on an electron
g Acceleration due to gravity
force Same as g
mole Avogadro's number
water Pressure head per unit height of water
au Astronomical unit.
EXAMPLES
To start the units command, enter:
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UNITS(1,C) AIX Commands Reference UNITS(1,C)
units
Now you can try the following examples. In these examples, the text that you
enter is shown in "bold type" and the output from units is shown in "non-bold
type".
1. To display conversion factors:
you have: in
you want: cm
* 2.540000e+00
/ 3.937008e-01
The output from units tells you to multiply the number of inches by
"2.540000e+00" to get centimeters, and to divide the number of inches by
"3.937008e-01" to get centimeters.
These numbers are in standard exponential notation, so "3.937008e-01" means
"3.937008" * "10(-1)", which is the same as "0.3937008". The second number
is always the reciprocal of the first. That is, "2.54 = 1" / "0.3937008".
2. To convert a measurement to different units:
you have: 5 years
you want: microsec
* 1.577846e+14
/ 6.337753e-15
The output shows that "5 years" equals "1.577846*10(14)" microseconds, and
that one microsecond equals "6.337753*10(-15)" 5-year periods.
3. To give fractions in measurements:
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:
you have: 1.2-5 gal
you want: floz
* 1.536000e-03
/ 6.510417e+02
The expression "1.2-5 gal" stands for "1.2*10(-5)". Do not type an e
before the exponent. This example shows that "1.2*10(-5)" ("0.000012")
gallons equal "1.536*10(-3)" ("0.001536") fluid ounces.
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UNITS(1,C) AIX Commands Reference UNITS(1,C)
5. To specify complex units:
you have: gram centimeter/second2
you want: kg-m/sec2
* 1.000000e-05
/ 1.000000e+05
The units gram centimeter/second2 mean "grams * centimeters / second(2)."
Similarly, kg-m/sec2 means "kilograms * meters / sec(2)," which is often
read as "kilogram-meters per seconds squared." You can show multiplication
of units with a - (hyphen) or with a blank.
6. If the units you specify after "you have" and "you want" are
incompatible:
you have: ft
you want: lb
conformability
3.048000e-01 m
4.535924e-01 kg
The message "conformability" means that the units you specified cannot be
converted. Feet measure length, and pounds measure mass, so converting
from one to the other doesn't make sense. Therefore, the units command
displays the equivalent of each value in standard units.
In other words, this example shows that one foot equals "0.3048" meters and
that one pound equals "0.4535924" kilograms. units shows the equivalents
in meters and kilograms because the command considers these units to be
"standard" measures of length and mass.
FILES
/usr/lib/unittab List of units used by the units command.
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