the tasks can be anything...from changing a
string literal to writing documentation to altering behavior of the program to writing a brand new program.
You could be asked to write some database queries, to write a perl script to do something, to check a bunch of files into a code repository.
The number of things you COULD be asked to to are almost endless.
There are only two hard things in computer science: cache invalidation, naming things, and off-by-one errors