script to make random junk files of specific sizes

mkdata.sh

#!/bin/sh
set -e

function randomfile {
  local numbytes="$1"
  local outfile="$2"

  { cat /dev/urandom |    # read random byte stream
    base64 |              # base64-encode the garbage so it's safely printable
    fold -w 79 |          # fold lines at 79 chars (80 char line w/ newline)
    head -c"$numbytes"    # read n chars then stop
  } > "$outfile"

  echo "$(cat "$outfile" | wc -c) random bytes written to $outfile"
}

randomfile 50000 ./data1.txt
randomfile 20 ./data2.txt

echo "Done."