[GRASS-dev] [GRASS GIS] #3747: Allow appending instead of overwriting an output file in relevant statistics or attribute reporting modules

[GRASS GIS]

#3747: Allow appending instead of overwriting an output file in relevant
statistics or attribute reporting modules
------------------------------+-------------------------
 Reporter:  Nikos Alexandris  |      Owner:  grass-dev@…
     Type:  enhancement       |     Status:  new
 Priority:  normal            |  Milestone:
Component:  Default           |    Version:  unspecified
 Keywords:                    |        CPU:  Unspecified
 Platform:  Unspecified       |
------------------------------+-------------------------
 We frequently report statistics for multiple maps. It would be very useful
 to allow appending to an existing file, instead of overwriting it, by
 adding a flag/parameter to relevant modules such as
 https://grass.osgeo.org/grass76/manuals/r.stats.html or even
 https://grass.osgeo.org/grass76/manuals/r.univar.html.

 (The latter, though, computes the overall statistics if many maps are
 given as an input. Perhaps a flag could allow for a serial output of
 statistics for each input raster map separately.)

 Here a suggested example (verified that works) for `r.stats`, in the
 context of this thread https://lists.osgeo.org/pipermail/grass-
 dev/2018-August/089377.html:

 {{{
 Index: raster/r.stats/main.c
 ===================================================================
 --- raster/r.stats/main.c       (révision 72717)
 +++ raster/r.stats/main.c       (copie de travail)
 @@ -223,7 +223,7 @@

      name = option.output->answer;
      if (name != NULL && strcmp(name, "-") != 0) {
 -       if (NULL == freopen(name, "w", stdout)) {
 +       if (NULL == freopen(name, "a", stdout)) {
             G_fatal_error(_("Unable to open file <%s> for writing"),
 name);
         }
      }
 }}}

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Ticket URL: <https://trac.osgeo.org/grass/ticket/3747>
GRASS GIS <https://grass.osgeo.org>