[GRASS-dev] Re: [GRASS GIS] #181: tac command missing in OSX

[GRASS GIS]

#181: tac command missing in OSX
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  Reporter:  kyngchaos  |       Owner:  grass-dev at lists.osgeo.org
      Type:  defect     |      Status:  new                      
  Priority:  minor      |   Milestone:  6.3.1                    
 Component:  default    |     Version:  6.3.0                    
Resolution:             |    Keywords:  v.in.garmin, v.in.mapgen 
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Comment (by 1gray):

 Replying to [comment:10 glynn]:
 > Replying to [comment:9 hamish]:

 ![...]

 > > awk would be a great solution as this is fed directly into that. But
 > > I have no idea how to write that.

 > Replace:
 > `... | tac | ...`
 > with:
 > `... | awk '{print NR,$0}' | sort -nr | sed 's/^[0-9]* //' | ...`

 I see no reason to use Awk to number lines, since there's
 [http://www.opengroup.org/onlinepubs/000095399/utilities/nl.html nl].
 Neither I see a reason to use `sort`, since Awk has arrays:
 {{{
 awk_tac () {
     awk '1 { last = NR; line[last] = $0; } END { for (i = last; i > 0;
 i--) { print line[i]; } }'
 }

 if [ -n "$TAC" ] ; then
     ## do nothing
 elif type tac ; then
     TAC=tac
 else
     TAC=awk_tac
 fi

 ... | $TAC | ...
 }}}

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Ticket URL: <https://trac.osgeo.org/grass/ticket/181#comment:11>
GRASS GIS <http://grass.osgeo.org>