Shell Programming and Scripting

$ cat ppid.awk

BEGIN {
        OFS="\t"
        D=0

        do
        {
                D++

                while(getline<("/proc/" PID "/status"))
                {
                        if($1 == "Name:")       NAME=$2
                        if($1 == "PPid:")       PPID=$2
                }

                close("/proc/" PID "/status");

                print D, "PID", PID, "PPID", PPID, "NAME", NAME;

                PID=PPID;       NAME="";        PPID=""
        } while(PID>0)

        exit 1
}

$ awk -v PID="$$" -f ppid.awk

1       PID     6925    PPID    6924    NAME    bash
2       PID     6924    PPID    6921    NAME    sshd
3       PID     6921    PPID    3937    NAME    sshd
4       PID     3937    PPID    1       NAME    sshd
5       PID     1       PPID    0       NAME    init

$