Creating package for Mac in Windows / Linux
# random DNA function
randDNA = function(n){
paste(sample(c("A", "C", "T", "G"), n, replace = TRUE), collapse = "")
}
# DNA to RNA function
dna2rna <- function(inputStr) {
  if (!is.character(inputStr))
    stop("need character input")
  is = toupper(inputStr)
  chartr("T", "U", is)
}

# complementary sequence function
compSeq <-  function(inputStr){
 chartr("ACTG", "TGAC", inputStr)
 }

# example data
dnaseq1 <- c("ATTGTATCTGGGTATTTCCCTTAATTGGGGCCTTT")
dnaseq2 <- c("TGGGGTAAACCCGGTTTAAAATATATATATTTTT")
myseqdata <- data.frame(dnaseq1, dnaseq2)
save(myseqdata, file = "myseqdata.RData")

require(utils)
package.skeleton(list = c("randDNA","dna2rna", "compSeq", "myseqdata"),
name = "dnatool",environment = .GlobalEnv, path = "c:", force = FALSE)

C:Rtoolsbin;C:Rtoolsperlbin;C:RtoolsMinGWbin;
C:Program FilesRR-2.14.2binx64;

c:  repackage>  R CMD build dnatool
c:  repackage>  Rcmd build dnatool

c:  repackage> R CMD check dnatool

Unix source:     dnatool.tar.gz
Mac OS X binary: dnatool.tgz

$ tar -zcvf dnatool.tar.gz/home/dnatool