Resolved [Applescript] Security Framework issue

I was looking for running a shell command as root without asking the password to the user (except the first time), so I've decided to go through the Security Framework making a keychain to store and retrieve it in security but, as long as the Terminal prints the correct password:

Code:

password: "the_password"

doing the same from within Applescript, it returns me an empty string!
The code who give me that problem is:

Code:

set rootPassword to word 2 of (do shell script "security find-generic-password -gs \"my_service\" | tail -n 0")

Obviously, the keychain is made in order to allow the security command to access everything without asking for a password.

P.S.: I've tried to remove both the tail part and the word 2 of one in the Applescript code and it prints every line except the one that I need.

 

I've resolved using

Code:

set rootPassword to word 2 of (do shell script "security 2>&1 >/dev/null find-generic-password -gs \"my_service\"")