There is a way and it is actually has been explained in I believe /org/pantheon/desktop/behavior which is seems like settings area that we can access with dconf-editor (or you can see .xml version of it at /usr/share/glib-2.0/schemas/org.pantheon.desktop.gala.gschema.xml)
If you just put a single command, it will be used for every hotcorner
assigned to 'custom-command'. If you instead use the pattern
specific commands will be used per hotcorner. Possible identifiers are
'hotcorner-[topleft; topright; bottomleft; bottomright]' followed by a
':' and then the command. ';;' is used as delimiter between command
So I am using a devilspie command for minimizing all windows as you can find from here How can I view the desktop?
which requires for me to write :
at Custom Command are of System-Settings / Desktop / Hot Corners.
Also I have to choose bottom-right (my choice) hot corner as Execute Custom Command right.
However, as in your case if I want to use a custom command at bottom-left hot corner e.g. firefox, I have to change my custom code as:
after that simply choosing both bottom corners as Execute Custom Command will be enough to solve your problem.
So if your
left argument code is at
/home/[user]/left.sh and if your
right argument code is at
should solve it.
P.S.: This answer was for assuming you wanted to create two different custom script for each left and right arguments and use them in different corners.