Nothing
##' run system command
##'
##'
##' @title exec
##' @param command system command to run
##' @return An `exec` instance that stores system command outputs
##' @export
##' @author Guangchuang Yu
exec <- function(command) {
res <- system(command, intern=TRUE)
structure(res, class = "exec")
}
##' @method print exec
##' @export
print.exec <- function(x, ...) {
cat(x, sep='\n')
}
has_bin <- function(bin) {
os <- which_os()
which <- "which"
if (os == "Windows") {
which <- "where"
}
command <- sprintf("%s %s", which, bin)
exit_code <- system(command,
ignore.stdout = TRUE,
ignore.stderr = TRUE)
return(exit_code == 0)
}
##' test for internect connection via reading lines from a URL
##'
##'
##' @title has_internet
##' @param site URL to test connection
##' @return logical value
##' @export
##' @author Guangchuang Yu
has_internet <- function(site = "https://www.baidu.com/") {
ret <- tryCatch(
suppressWarnings(readLines(site, n = 1)),
error = function(e) NULL
)
return(!is.null(ret))
}
which_os <- function() {
Sys.info()[1]
}
user_dir <- function(appname = NULL, appauthor = NULL, ...) {
dir <- rappdirs::user_data_dir(
appname = appname,
appauthor=appauthor,
...)
if (!dir.exists(dir)) dir.create(dir, recursive = TRUE)
return(dir)
}
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