Input arguments (flags like) through command line to R

options.R

#Rscript filename.R --host= --dbname= --user= --password=
options<-paste0("--",c("host","dbname","user","password"))
args <- commandArgs(TRUE)
if(length(args)!=4)stop("Please input the full options of host, dbname, user and password.")

db.options<-function(option){
  option.location <- grepl(option,args)
  if(sum(option.location)!=1)
    stop(paste0("Something wrong with ", option, "."))
  if(!grepl("=",args[option.location]))
    stop(paste0("Value needed in ", option, "."))
  gsub(paste0("^",option,"="),"",args[option.location])
}

config<-vector()

for(option in options){
  config[gsub("^--","",option)]<-db.options(option)
}