Re: Awk not ouputting results via echo

[Lester Anderson <arctica1963@gmail.com>]

As  a test I did a simple function to read the inputs:

#!/bin/sh
lon_min=-12
lon_max=0
lat_min=28
lat_max=39
R_d=167
R_i=20
function Test() {
    echo Test function: $lon_min $lon_max $lat_min $lat_max $R_d $R_i
    }
#
Test > test.txt
# test.txt -> -12 0 28 39 167 20

Still needs awk to do those fiddly bits!

Lester

On 23 November 2015 at 16:24, Lester Anderson <arctica1963@gmail.com> wrote:
> Hi Eliot,
>
> I can see the logic of the function, but not sure how it is
> implemented from the section I have:
>
> lon_min=-12
> lon_max=0
> lat_min=28
> lat_max=39
> R_d=167
> R_i=20
>
> echo $lon_min $lon_max $lat_min $lat_max $R_d $R_i |
> awk "{R_t=6370;
>       pi=3.14159;
>       lat_av=(($lat_max+$lat_min)/2)*(pi/180.);
>       lon_av=(($lon_min+$lon_max)/2);
>       d_lat_e=($R_d/R_t)*180./pi;
>       d_lon_e=($R_d/(R_t*cos(lat_av)))*180./pi;
>       d_lat_i=($R_i/R_t)*180./pi;
>       d_lon_i=($R_i/(R_t*cos(lat_av)))*180./pi;
>       lon_e_min=$lon_min-d_lon_e;
>       lon_e_max=$lon_max+d_lon_e;
>       lat_e_min=$lat_min-d_lat_e;
>       lat_e_max=$lat_max+d_lat_e;
>       lon_i_min=$lon_min-d_lon_i;
>       lon_i_max=$lon_max+d_lon_i;
>       lat_i_min=$lat_min-d_lat_i;
>       lat_i_max=$lat_max+d_lat_i;
>       print lon_e_min,lon_e_max,lat_e_min,lat_e_max,lon_i_min,lon_i_max,lat_i_min,lat_i_max,lat_av*180./pi,lon_av;
> }" | read lon_e_min lon_e_max lat_e_min lat_e_max lon_i_min lon_i_max
> echo $lon_e_min $lon_e_max $lat_e_min $lat_e_max $lon_i_min $lon_i_max
> $lat_i_min $lat_i_max $lat_av $lon_av
>
> Do you have an example function that shows the workflow? Sorry not an
> awk/cygwin expert!
>
> Thanks
> Lester
>
> On 23 November 2015 at 15:23, Eliot Moss <moss@cs.umass.edu> wrote:
>> Ok, I think I have a sense of an underlying problem here.
>>
>> When you do:  ... | read v1 v2 ...
>>
>> The read executes in an inferior process, setting variables there.
>> The process then exits and you have no bindings in the parent shell,
>> which is where you want them.
>>
>> Maybe something like this would suit you better:
>>
>> myfunction() {
>>   ... stuff using positional arguments $1, $2, etc.
>> }
>>
>> myfunction $(awk blah ...)
>>
>> This take the output of the invocation of awk and puts it
>> where $(awk ...) was, which will invoke myfunction with
>> the line, parsing it into separate arguments (I believe).
>>
>> You could also capture the line using something like this:
>>
>> line="$(awk ...)"
>>
>> and then you can fiddle the result however you want, but I think that
>> calling a function (or another script) is probably simpler here.
>>
>> Regards -- Eliot Moss
>>
>>
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