how to check null variable

Shell Programming and Scripting
1

korn shell

If [ "$a" != "" ]
then
update_smartcare_user_password "$u_id"
else
echo "Not a database user"
fi

i get this error
Syntax error at line *** : `then' is not expected.
what should i do.

I want to check whether $a is null or not.

2 
if [ "$a" != "" ]
then
     update_smartcare_user_password "$u_id"
else
     echo "Not a database user"
fi

I presume the 'I' was supposed to be 'i'?

3

thank you very much porter. It was 'I' that wasted my hour. Seriouly debugging sucks when you have couple of hundreds lines of code. once again thanx