newbie in awk

[wally1]

Hi i am a newbie in awk,
this is the first script that i try to run but i have made a mistake because i haven't output on my screen.
Please this is my little awk program :

#! /bin/ksh
ls -l | awk '$5 == "Aug" { sum = sum+$4 } END { print SUM}'

i run this script with this command
> ./pippo.ksh

Anyone can help me to find the error ?????
Walter

 

[Salem]

AWK is case-sensitive, so try

print sum

at the end

 

[wally1]

Ok i put sum but i haven't the output.
Why ????
Walter

 

[wally1]

I have made a mistake to count the fields in a generic record of output of ls -l command.
Now is ok all
Thanks all
Walter

 

[rakeshs859]

Wally,

Awk is case sensitive. Look at your variables for "sum" and then you are using "SUM" to print it out which will give you blank results.