I am trying to install a package from github, but I keep getting an error when I
library(devtools) install_github(repo="swirl", username="ncarchedi") Installing github repo(s) swirl/master from ncarchedi Downloading swirl.zip from https://github.com/ncarchedi/swirl/archive/master.zip Error in function (type, msg, asError = TRUE) : error setting certificate verify locations: CAfile: /Library/Frameworks/R.framework/Versions/3.0/Resources/library/RCurl/CurlSSL/cacert.pem CApath: none
I have tried to install several different packages
(including an updated version of ggmap), and I always get the same error. It
must have something to do with RCurl, but I don't understand what the problem
is, or how to fix it. I have devtools (Version 1.3) and RCurl
(Version 1.95-4.1). I am running R version 3.0.1 ("Good Sport") on mac.
sessionInfo() R version 3.0.1 (2013-05-16) Platform: x86_64-apple-darwin10.8.0 (64-bit) locale:  en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8 attached base packages:  stats graphics grDevices utils datasets methods base other attached packages:  RCurl_1.95-4.1 bitops_1.0-5 devtools_1.3 loaded via a namespace (and not attached):  digest_0.6.3 evaluate_0.4.3 httr_0.2 memoise_0.1 parallel_3.0.1 stringr_0.6.2  tools_3.0.1 whisker_0.3-2