Change the output precision of data sets

precision {<filename> | <dataset arg>} [<width>] [<precision>]

Set the precision for all data sets in data file <filename> or data set(s) specified by <dataset arg> to width.precision, where width is the column width and precision is the number of digits after the decimal point. Note that the <precision> argument only applies to floating-point data sets.
For example, if one wanted to set the precision of the output of an RMSD calculation to 8.3, the input could be:

trajin ../
rms first :10-260 out prec.dat
precision prec.dat 8 3

and the output would look like:

#Frame RMSD_00000
1 0.000
2 0.630