$GOBIN is not a directory or doesn't exist

Proceeding with the google go tutorial, write the following commands:

cd $GOROOT/src --> this should show that you are inside the folder go/src
./all.bash ..> if this command display the following message:

$GOBIN is not a directory or doesn't exist

Then, go to the go/src folder and create a new folder and name it bin, as previously in the environment variable, we set the GOBIN=/home/dinahelmy/go/bin, and the bin folder is not there, then just create it and write again ./all.bash command once more. If it works fine, we will get something like that at the end: 3 known bugs; 0 unexpected bugs