title: R unwantedly converting character to date instead of numeric
body: <p>I'm passing arguements from a shell script to an R script and R.</p>
  
  <pre><code>library(rLandsat) #used later in the script
  args&lt;-commandArgs(trailingOnly=TRUE)
  
  max_date = Sys.Date()-as.numeric(args[1])
  min_date = Sys.Date()-(as.numeric(args[1])+as.numeric(args[2]))
  path&lt;-as.numeric(as.character(args[4]))
  row&lt;-as.numeric(as.character(args[5]))
  cloud&lt;-as.numeric(as.character(args[6]))
  foldername&lt;-as.character(args[7])
  for(i in args){
      print(typeof(i))
  }
  print(args)
  print(c(max_date,min_date,path,row,cloud,foldername))
  for(i in c(max_date,min_date,path,row,cloud,foldername)){
      print(typeof(i))
  }
  </code></pre>
  
  <p>and R is for some reason converting the arguments to some type of date that is still a character. Here is the output from the script. <code>args[3]</code> is used later but I should probably check that too. I know the <code>arg</code> is already a character but it returned the same values with only <code>as.numeric()</code> for <code>path row</code> and <code>cloud</code>. The first two arguments are returned correctly <code>"2016-12-31" "2016-01-01"</code> but the others I would like the same value as the original argument returned. Will check out <code>list()</code> instead of <code>c()</code></p>
  
  <pre><code>[1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "1048"        "365"         "Yellowstone" "38"          "29"
  [6] "20"          "2016"
  [1] "2016-12-31" "2016-01-01" "1970-02-08" "1970-01-30" "1970-01-21"
  [6] "1975-07-10"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  [1] "character"
  </code></pre>