gshhs_to_polygon gshhs_f.b > VERSION_final_dbase.b
gshhs_to_polygon gshhs_h.b > VERSION_final_dbase_0.2km.b
gshhs_to_polygon gshhs_i.b > VERSION_final_dbase_1km.b
gshhs_to_polygon gshhs_l.b > VERSION_final_dbase_5km.b
gshhs_to_polygon gshhs_c.b > VERSION_final_dbase_25km.b
where VERSION should match the current definition in the makefile (e.g., v4.2).
mapproject polygon.1 -G237.59/47.6745 | awk '{if ($3 < 200) print NR, $0}'
This will echo out all points within 200 m of the given coordinate in -G. Edit polygon.1, goto the line in question. Then, use zoom.sh to make a plot of the area that shows each point as a dot. Visually identify which points to replace and where to insert the new segment, and then identify those points in the polygon.1 file. Remove and insert accordingly, and save polygon.1. Now move polygon.1 to the sub-directory pol.