1 .TH UNITS 1
2 .if n .ds / /
3 .SH NAME
4 units \- conversion program
5 .SH SYNOPSIS
6 .B units
7 [
8 .B -v
9 ]
10 [
11 .I file
12 ]
13 .SH DESCRIPTION
14 .I Units
15 converts quantities expressed
16 in various standard scales to
17 their equivalents in other scales.
18 It works interactively in this fashion:
19 .IP
20 .EX
21 you have: inch
22 you want: cm
23     * 2.54
24     / 0.393701
25 .EE
26 .PP
27 A quantity is specified as a multiplicative combination
28 of units and floating point numbers.
29 Operators have the following precedence:
30 .IP
31 .EX
32 .ta \w'\fLXXXXXXXXXXXXXXX'u
33 \fL+\fP \fL-\fP	\f1add and subtract
34 \fL*\fP \fL/\fP \fL×\fP \fL÷\fP	\f1multiply and divide
35 catenation	multiply
36 \fL²\fP \fL³\fP \fL^\fP	\f1exponentiation
37 \fL|\fP	\f1divide
38 \fL(\fP ... \fL)\fP	\f1grouping
39 .EE
40 .PP
41 Most familiar units,
42 abbreviations, and metric prefixes are recognized,
43 together with a generous leavening of exotica
44 and a few constants of nature including:
45 .IP
46 .de fq
47 \fL\\$1\\fP	\\$2 \\$3 \\$4 \\$5 \\$6
48 ..
49 .ta \w'\fLwaterXXX'u
50 .nf
51 .fq pi,\f1π\fP ratio of circumference to diameter
52 .fq c speed of light
53 .fq e charge on an electron
54 .fq g acceleration of gravity
55 .fq force same as \fLg\fP
56 .fq mole Avogadro's number
57 .fq water "pressure head per unit height of water"
58 .fq au astronomical unit
59 .fi
60 .PP
61 The
62 .L pound
63 is a unit of
64 mass.
65 Compound names are run together, e.g.
66 .LR lightyear .
67 British units that differ from their US counterparts
68 are prefixed thus:
69 .LR brgallon .
70 Currency is denoted
71 .LR belgiumfranc ,
72 .LR britainpound ,
73 etc.
74 .PP
75 The complete list of units can be found in
76 .BR \*9/lib/units .
77 A
78 .I file
79 argument to
80 .I units
81 specifies a file to be used instead of
82 .BR \*9/lib/units.
83 The
84 .B -v
85 flag causes
86 .I units
87 to print its entire database.
88 .SH EXAMPLE
89 .EX
90 you have: 15 pounds force/in²
91 you want: atm
92     * 1.02069
93     / .97973
94 .EE
95 .SH FILES
96 .B \*9/lib/units
97 .SH SOURCE
98 .B \*9/src/cmd/units.y
99 .SH BUGS
100 Since
101 .I units
102 does only multiplicative scale changes,
103 it can convert Kelvin to Rankine but not Centigrade to
104 Fahrenheit.
105 .PP
106 Currency conversions are only as accurate as the last time someone
107 updated the database.