A function that gets the full path of the currently running program. If the function fails to retrieve the path for some reason, it will return a NULL. The function takes no parameters.
Sys.path()The full path of the currently running program, or a NULL.
Other fileops: 
dir.find(),
file.find(),
source.all()
# Get current path
pth <- Sys.path()
pth
# [1] "C:/programs/myprogram.R"