URL query downloads linger

When I get the earthquake data from NEIC I run something like this

`gmt convert ${URL} -i2,1,3,4+s50,0 -hi1 > 3_quakes.txt`

where URL is built by the 3_get_quakes.sh script and is

`https://earthquake.usgs.gov/fdsnws/event/1/query.csv?starttime=2018-01-01%0000:00:00&endtime=2018-12-31%0000:00:00&minmagnitude=5&orderby=time-asc`

What happens is that we receive a _query.csv_ file which **gmt convert** reads and converts as indicated. However, _query.csv_ remains in the directory. Anyone who thinks that is bad and that we should find a way for GMT (here **gmt convert**) to delete it at the end?