Shell Programming and Scripting

last| awk 'NF>6&&!/logged in/ { gsub(/\(|\)/,"") 
                              split($NF,a,"[+:]")
                              b[$1]+=($NF~/+/)?a[1]*3600+a[2]*60+a[3]:a[1]*60+a[2]
                             }
          END{for (i in b) print b[i], i|"sort -rn|head -1" }' 

160949 panman82

$ whatis ac
ac (1)               - print statistics about users' connect time

awk: 0602-521 There is a regular expression error.
        ?*+ not preceded by valid expression.

ac -p | awk '
BEGIN {
    username = "none";
    total = 0;
}
$1 !~ /total/ {
    if ($NF > total) {
        username = $1;
        total = $NF;
    }
}
END {
    print username;
}
'

last | awk '
$2 ~ /console/ {
    gsub(/\(|\)/, "", $NF);
    split($NF, times, "[+:]");
    if ($NF ~ /\+/) {
        logins[$1] += times[1] * 1440;
        logins[$1] += times[2] * 60;
        logins[$1] += times[3];
    } else {
        logins[$1] += times[1] * 60;
        logins[$1] += times[2];
    }
}
END {
    username = "none";
    longest = 0;
    for (user in logins) {
        if (logins[user] > longest) {
            username = user;
            longest = logins[user];
        }
    }
    print username;
}
'

awk '$2 ~ /console/ { gsub(/\(|\)/,""); split($NF,a,"[+:]")
                      b[$1]+=($NF~/+/)?a[1]*1400+a[2]*60+a[3]:a[1]*60+a[2]
                      if (max<b[$1]) {max=b[$1];name=$1}
                    }END{print name}' infile