[R] update packages from local

[Wayne (Yanwei) Zhang]

Hi all,

I have an old package installed, say "abc". Now I made some changes to the source, 
and built a new version of the source code "abc_0.1.1.tar.gz". How can I update the 
old package to this newer version from the local tar.gz file? I was running the 
following, but it did not work.

setwd("directory where the tar.gz file locates")

update.packages(repos=NULL,pkgs="abc_0.1.1.tar.gz",type="source")

The code runs, but when I load library(abc) again, it is still the old version... What 
did I miss here?  Thanks.