[GRASS-user] to shorten lines

[Ivan Shmakov]

>>>>> ivan marchesini <marchesini at unipg.it> writes:

 > Many thanks Markus...

 > I did this way (for a line only, which has category=163 ... now I
 > will create a cycle for each line of the map):

 > with this I obtain the length of the line subtracted of 20 meters:
 > echo "`v.report map=Reticol layer=1 option=area units=meters | grep
 > 163 | cut -f3 -d'|'`-20" | bc -l

        You may find `sed' useful as well, e. g.:

$ v.report map=Reticol layer=1 option=area units=meters \
      | grep 163 \
      | cut -f3 -d'|' \
      | sed -e s/\$/-20/ \
      | bc -q

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