I am new to this linux business, and certainly not a coder, so if I say something goofy please correct me.

I am running Puppy 5.20 (now 5.25) on a 4 gb usb stick w/ 2 partitions: ext3 and fat32, changes saved to ext3.
Have been seeking a simple way to control saving sessions, in case of a mistake or an unwanted installation. Am assuming that:
- - like me, readers have limited knowledge of the OS and of script editing.
- - Puppy is on a usb stick, and not used as a permanent working OS, like on a HD.
If you make the 3 edits below, these 3 changes happen:
1. Session changes can still be saved at any time by clicking on the "Save" bullseye icon.
2. Session changes will not automatically save at shutdown.
3. At startup, you will get a warning message which says "X seems to have exited uncleanly the last time you ran puppy..." but no harm is done, just the changes you did not deliberately save are lost.
- - Click on "Ignore" and you will be in Puppy as it was at shutdown.
The lines to edit:
1. Open the console and type "geany /etc/rc.d/rc.shutdown" without quotes.
- - This opens the shutdown code for editing
2. Type cntrl f to search for "/usr/sbin/snapmergepuppy" without quotes.
- - /usr/sbin/snapmergepuppy is in my unaltered installation 3 times,
- - at line 817, line 847, and line 853.
3. Comment out each line that has it by typing #myrem in front of that line. The # sign alone comments it out, but use #myrem so you can find it later if you need to.

So for each line (3 of'em) that originally said
/usr/sbin/snapmergepuppy /initrd/pup_ro1 /initrd/pup_rw
you now have
#myrem /usr/sbin/snapmergepuppy /initrd/pup_ro1 /initrd/pup_rw
4. Save the file.
5. Added Feb 22 (should have been in this post from the start): "Go to "Menu->System->Puppy Event Manager->save session->save Interval", and set the value to zero [actually 0] minutes, and OK that."
Did I get it right?
It worked here. It is based on the solutions of many other members. Thank you.
edited May 3rd 2011 for clarity.