$0 – Program Name
system("ps -fp $$");
UID PID PPID STIME TTY TIME CMD grant 2265 2145 13:31 pts/7 00:00:00 /usr/bin/perl ./dollar-zero.pl
system("ps -fp $$");
UID PID PPID STIME TTY TIME CMD grant 2265 2145 13:31 pts/7 00:00:00 /usr/bin/perl ./dollar-zero.pl