Bash scripts are written for GMT 6.0.0. 
Katie Woods. 02 Aug 2022

Scripts can be run from command line, for example:
$ ./plot_NZ_inset.sh

DIRECTORIES:
colour_palettes/	.cpt files for plotting topography etc
data_examples/		data used in the examples
figures/	 	where output figures go (set on 'gmt begin' line in scripts)
files/		   	topography files etc

Figure output extension is set on 'gmt begin' line.
Usually I output in .pdf (preserves transparency features) and add extra 
annotions/convert to desired format using Inkscape.

For more GMT6 examples:
https://docs.generic-mapping-tools.org/6.0/gallery.html

Good sources of colourmaps:
http://soliton.vm.bytemark.co.uk/pub/cpt-city/views/totp-cpt.html
https://www.fabiocrameri.ch/colourmaps/