Shell Programming and Scripting

Hey guys, i'm trying to write a script which checks user input. If the input provided is wrong i.e. " " then I want to reprompt the user to enter it again and again etc. until it's OK.

Here's my code:

Code:

 
wp="wp"
ss="ss"
pf="pf"
echo "Welcome to the backup utility"
echo "what is your username?"
read username
if [[ $username == "" ]]
then
echo "No username provided"
while [ $username == ""]
do
echo "what is your username please?!"
read username
done
else
echo /home/$username

I can get it to reprompt the user for their name. However when I enter the name after 1 of these reprompts I get the error: line 10: [: ewan (the username I enter): unary operator expected.


Any suggestions?


Thanks


Ewan

There must be a space before this closing square bracket:

Code:

while [ $username == "" ]
                       ^

And double quotes around the variable.

Code:

while [ "$username" == "" ]

-or-
ksh/bash style double brackets:

Code:

while [[ $username == "" ]];