Bash if elif else fi

Bash If..elif..else..fi

 if [ conditional expression1 ]
 then
   statement1
   statement2
   .
 elif [ conditional expression2 ]
 then
   statement3
   statement4
   .
   .
   .
 else
   statement5
 fi

example

 if [ "$opt" = "some string" ]; then
   some_command
 fi

OR example

 if [[ "$VARIABLE" == "something" || "$VARIABLE" == "else" ]]; then
   some_command
fi

conditional based on string compare

if a variable contains a string...

string='foobar'
if  $string == *"bar"* ; then
  echo "your bar is in my foo!"
fi