[완료]cat이나 strings에서

#!/bin/bash
THIS='12345'
THAT=${THIS:0:3}
echo ${THAT}
^D

${parameter:offset:length}
   Substring Expansion.  Expands to up to length characters of parameter starting at the character specified by  off-
   set.   If  length is omitted, expands to the substring of parameter starting at the character specified by offset.
   length and offset are arithme....