bash shell script string comparison

Shell Programming and Scripting
1

I want to remove a line that has empty string at second field when I use cut with delimeter , like below

$cat demo
hello, mum
hello,
 
#!/bin/sh
 
while read line
do
if [ `cut -f 2 -d "," "$line" = "" ]
then
    # remove the current line command goes here
fi
done < "demo"

i got an error message for above command and I have no idea how to remove current line

can I use

sed 's/$0//'
2

use something like this

awk -F"," '{ if ($2!=" ") print $0}'

3 
awk -F, '$2' file > newfile

Regards

4

I am using if statement and I fixed it to

if [ `echo $line | cut -f 2 -d","`=="" ]
then
    echo ""
else
    echo $line
fi

but I get an error message below
[: ==: unary operator expected

can any one help me using if statement??

5 
if [ "`echo $line | cut -f 2 -d","`" = "" ]

Or:

if [ -z "`echo $line | cut -f 2 -d","`" ]