monsieur_champs:(1)$ units
1991 units, 71 prefixes, 32 nonlinear units
You have: 1 perl
You want: centimeters
        * 0.1880325
        / 5.3182296
You have: 1 perl 
You want: milimeters
        * 1.880325
        / 0.53182296
You have: 1 perl
You want: nanometers
        * 1880325
        / 5.3182296e-07
You have: 1 perl
You want: inches
        * 0.074028543
        / 13.508303