Возможная ошибка в Bash?: foo() { echo "${var[0]}"; }; var=(bar baz) foo

Попробуйте:

awk ' 
# if /^Studid/ is matched move to the next record (row) of the input text
/^Studid/ { next }
{               
    total=$3+$4+$5
    per=total/3
    if (per > 80)  
        print 
}' stud

output

   2       George      90        95       82
   4       Dennie      89        92       90