Comparing Strings in Shell

I am executing the below script.

#!/bin/sh
# Script to manipulate date
#

d="`date +%a`";
d1="Fri"
if [$d = $d1]
then
    echo "Hey Man! Today's $d"
fi

No matter how I modify it, it always gives me an error on the line "if [$d = $d1]" ... Fri command not found.

Please help.