Here is how the data files contained in this package were produced:

1) Download the following files from UCSC to a DOWNLOAD dir:

   ftp://hgdownload.cse.ucsc.edu/goldenPath/hg18/bigZips/
     chromFa.zip (900M)
     upstream1000.zip (6.3M)
     upstream2000.zip (12M)
     upstream5000.zip (29M)

2) Shell commands:

   cd DOWNLOAD
   for i in `ls *.zip` ; do unzip $i ; done
   for i in `ls *.gz` ; do gunzip $i ; done
   R CMD INSTALL BSgenome.Hsapiens.UCSC.hg18

3) R commands:

   library(BSgenome.Hsapiens.UCSC.hg18)
   file <- system.file("scripts", "comments.R", package="BSgenome.Hsapiens.UCSC.hg18")
   source(file)
   buildDataFiles("DOWNLOAD", "DATA", seqnames(Hsapiens), "", ".fa", seqcomments)
   buildDataFiles("DOWNLOAD", "DATA", mseqnames(Hsapiens), "", ".fa", mseqcomments, FALSE)

