Extract content between the first " and the last " double quotes
s='Test "checkin_resumestorevisit \"- "Online_V2.mt" Run'; s=${s#*'"'}; s=${s%'"'*}; echo "$s"
Thanks to this user: https://stackoverflow.com/a/35636373/2394635
Sample Output
checkin_resumestorevisit \"- "Online_V2.mt
man ls