units is a command which help us to convert between different units of measure like feet into meter etc.
Let us see few examples
ram@rhlaptop:~$ units
2411 units, 71 prefixes, 33 nonlinear units
You have: foot
You want: cm
* 30.48
/ 0.032808399
You have: acre
You want: meter^2
* 4046.8726
/ 0.00024710439
You have: tempF(100)
You want: tempC
37.777778
As you can see it is pretty useful. How to interpret the results?. The first line if has a * means it should be multiplied.
For example in foot to cm conversion, following formula helps
1 foot = 30.48 * 1cm.
The second line shows the reverse, i.e cm to foot conversion, here division should be applied. For example cm to foot
cm =foot / 0.032808399
You can even give exact value that you want to convert. Say 10feet
You have: 10feet
You want: cm
* 304.8
/ 0.0032808399
As for as non-linear units like Fahrenheit to Celsius, there is a function like syntax as you can see in the third example.
The information about units is usually at /usr/share/misc/units.dat. A look at this file is good as it throws lot of information – reminding me about clarke’s table in school/college days.