In response to a previous question, Alternatives to system() in R for calling sed, rsync, ssh etc.: Do functions exist, should I write my own, or am I missing the point?, hadley's answer indicated that when faced with a similar problem, he had used a function like:
bash <- function() system("bash")
I found the original in his devtools package; implemented in devtools/R/bash.R:
#' Open bash shell in package directory.
#'
#' @param pkg package description, can be path or package name. See
#' \code{\link{as.package}} for more information
#' @export
bash <- function(pkg = NULL) {
pkg <- as.package(pkg)
in_dir(pkg$path, system("bash"))
}
I don't understand the point of this. When I issue
bash <- function() system("bash")
It sends me to the bash shell, after which exit returns me to the R session, but there is no bash function. It seems that I can get the same effect by either issuing either of the following command pairs (first command in R, second in bash)
system('bash')
exit
or
q('yes')
R
the striked part were due to a copy/paste error on my part
I also can not find any further uses of the bash function in the devtools package
Can someone please help me understand how the bash function could be used; can it be used in contexts (e.g. within scripts or functions) other than interactive R mode?
Earlier versions of devtools included some functionality to push/pull code to git/github. This has now been deprecated.
Instead, the convenience function bash simply opens a bash editor in the package directory. This means you can use command line tools to interact with git/github.
The purpose of bash is simply to save a few keystrokes to open the command line in the package directory. It serves no other function.