| .TH UNITS 1 |
| .if n .ds / / |
| .SH NAME |
| units \- conversion program |
| .SH SYNOPSIS |
| .B units |
| [ |
| .B -v |
| ] |
| [ |
| .I file |
| ] |
| .SH DESCRIPTION |
| .I Units |
| converts quantities expressed |
| in various standard scales to |
| their equivalents in other scales. |
| It works interactively in this fashion: |
| .IP |
| .EX |
| you have: inch |
| you want: cm |
| * 2.54 |
| / 0.393701 |
| .EE |
| .PP |
| A quantity is specified as a multiplicative combination |
| of units and floating point numbers. |
| Operators have the following precedence: |
| .IP |
| .EX |
| .ta \w'\fLXXXXXXXXXXXXXXX'u |
| \fL+\fP \fL-\fP \f1add and subtract |
| \fL*\fP \fL/\fP \fL×\fP \fL÷\fP \f1multiply and divide |
| catenation multiply |
| \fL²\fP \fL³\fP \fL^\fP \f1exponentiation |
| \fL|\fP \f1divide |
| \fL(\fP ... \fL)\fP \f1grouping |
| .EE |
| .PP |
| Most familiar units, |
| abbreviations, and metric prefixes are recognized, |
| together with a generous leavening of exotica |
| and a few constants of nature including: |
| .IP |
| .de fq |
| \fL\\$1\\fP \\$2 \\$3 \\$4 \\$5 \\$6 |
| .. |
| .ta \w'\fLwaterXXX'u |
| .nf |
| .fq pi,\f1π\fP ratio of circumference to diameter |
| .fq c speed of light |
| .fq e charge on an electron |
| .fq g acceleration of gravity |
| .fq force same as \fLg\fP |
| .fq mole Avogadro's number |
| .fq water "pressure head per unit height of water" |
| .fq au astronomical unit |
| .fi |
| .PP |
| The |
| .L pound |
| is a unit of |
| mass. |
| Compound names are run together, e.g. |
| .LR lightyear . |
| British units that differ from their US counterparts |
| are prefixed thus: |
| .LR brgallon . |
| Currency is denoted |
| .LR belgiumfranc , |
| .LR britainpound , |
| etc. |
| .PP |
| The complete list of units can be found in |
| .BR \*9/lib/units . |
| A |
| .I file |
| argument to |
| .I units |
| specifies a file to be used instead of |
| .BR \*9/lib/units. |
| The |
| .B -v |
| flag causes |
| .I units |
| to print its entire database. |
| .SH EXAMPLE |
| .EX |
| you have: 15 pounds force/in² |
| you want: atm |
| * 1.02069 |
| / .97973 |
| .EE |
| .SH FILES |
| .B \*9/lib/units |
| .SH SOURCE |
| .B \*9/src/cmd/units.y |
| .SH BUGS |
| Since |
| .I units |
| does only multiplicative scale changes, |
| it can convert Kelvin to Rankine but not Centigrade to |
| Fahrenheit. |
| .PP |
| Currency conversions are only as accurate as the last time someone |
| updated the database. |
