vector length

[Nancy Greeley]

We have vector files representing tributaries to a river.
Is there a command in GRASS4.0 or 
4.1 that will give me the vector length of either 1) each category
in a file or 2) the whole vector file?

Background:  The vector files are dlg stream data which are imported into
GRASS4.0.  We can use v.digit to either categorize all the tributaries in 
each file  by
stream order (in which case we'd like to use choice #1, above)
OR we can create files containing only the first order tributaries, 
then create a file containing only the 2d order tributaries, etc (in which 
case we'd like to use choice #2, above).

Thanks in advance for all help!
-Nancy