Probably something like this script:
gmt begin map png
gmt coast -R25.5/45.5/34.5/42.5 -JM6i -Gwhite -S0/200/255 -U -I9/0/0/255 -I1/0/0/255 -I2/0/0/255 -B
gmt xyz2grd cureqandtbl1.csv -R26/44/35/41.9375 -I10k -Gtr.nc
gmt grdcontour tr.nc -S4 -Ncont.cpt
gmt end show
It should create the PNG file map.png and open it for you to view.