In PyMOL 2 and newer, loading a new PDB file will automatically display molecules in cartoon mode. There are 10 cartoon modes available in PyMOL (mine version 2.3).

The 10 modes are: arrow, automatic (default), dash, dumbbell, loop, oval, putty, rectangle, skip and tube.

Using ubiquitin 1UBQ as model to display 9 of 10 cartoon modes (cartoon skip is not shown, as it “skips” cartoon).

type “cartoon arrow” in the command line, you will see below

cartoon dash,

cartoon dumbbell

cartoon loop,

cartoon oval,

cartoon putty (based on b-factor, no color gradient)

cartoon rectangle (like cartoon arrow, but no “arrow” displayed)

cartoon tube