[Phys-l] unit calculator

[John Denker <jsd@av8n.com>]

On unix there exists a utility called "units" that will do simple
calculations including the units.  Example:


> You have: 1 furlong per fortnight
> You want: 
>         Definition: 0.00016630952 m / s
> You have: 
> You have: 
> You have: 
> You have: 1 e
> You want: 
>         Definition: 1.6021765e-19 A s
> You have: 
> You have: 
> You have: 1 coulomb
> You want: e
>         * 6.2415097e+18
>         / 1.6021765e-19
> You have: 
> You have: 
> You have: 
> You have: pi
> You want: 
>         Definition: 3.1415927
> You have: 
> You have: 
> You have: sin(pi)
> You want: 
>         Definition: 1.2246064e-16




Apparently it has been around since 2004 or earlier, but I only recently
found out about it.  To install it all I had to do was
    apt-get install units
Sigh.

There's also a thing called units-filter, where the output format is
more machine-readable (and less human-readable).