What is the Unix (QNX) equivalent of Windows command line "dir /s /b"

There isn't a flag for ls which will do what you ask, but you can accomplish it with several other tools, the easiest being (possibly) find:

find .

find may give you all that you need. It has a little more overhead as it performs more tests than ls alone, but if you want the path information in the output then this may be the simplest way to achieve that.

If you're going to compare two systems, then you should probably do some text editing first and swap \ with /, and remove the C: prefix. Then sort the lists and use diff to spot the changes. sed will be your friend here. Follow-up with a comment if you want this too.

tree -if

-i to not indent -f to print path