tr命令
==========


uppcase all chars::

   $ echo "aBcDeF" |tr abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ  // ABCDEF
   or
   $ echo "aBcDeF" |tr '[:lower:]' '[:upper:]'



uppcase the first char::

   TYPE='abCdeFg'
   PREFIX="$(tr '[:lower:]' '[:upper:]' <<< ${TYPE:0:1})${TYPE:1}"
   echo $PREFIX