How to do a logical OR operation in shell scripting

Question

I am trying to do a simple condition check, but it doesn\'t seem to work.

If $# is equal to 0 or is greater than 1 then say he

Answer 1

Sometimes you need to use double brackets, otherwise you get an error like too many arguments

if [[ $OUTMERGE == *"fatal"* ]] || [[ $OUTMERGE == *"Aborting"* ]]
  then
fi