Programming :: Shell Scripting Loop Error Yal2361: Command Not Found?

I have written the following script in my linux server to add users for LDAP database.But i can't able to run this.

The script is as following

#!/bin/bash
echo "Mention the username which you want to convert LDIF format"
read username
if ["$username" -e "/ldiffile/passwd"]; then
echo "Username already exists"
else
cat /etc/passwd | grep -i "$username" >> /ldiffile/passwd
fi
The output which i got :
. ldapadd.sh
Mention the username which you want to convert LDIF format
yal2361
-bash: [yal2361: command not found

please let me know where need to change and what