/GrADS/script/v2s.gsf

ret = v2s( var )

test.gs

'reinit'
rc = gsfallow( 'on' )
'open t.ctl'
'set lat 0'
'set lon 0'
'set t 1'
'gm = aave(t, global)'
gm = v2s('gm')
say gm
ga-> test
286.429