Use of rm(list=ls()) at Start of Job

Yes, it can be useful to start off your batch script with the command 'rm(list=ls())' just to make sure that you have a clean R environment before submitting the batch job. For example, you may have users that have their own .Rprofile files with a sequence of commands in them that create some R objects on startup of R. In that case it may be useful, to erase any existing R objects before running the R code for the batch job.

For example, here is pseudocode to do this:

x <- ls() 
if (x is not empty) { 
rm(list=ls() 
}

Yes, you can certainly run code like this after startup to remove existing R objects from the user workspace.