# cat /proc/uptime
The first number is the total number of seconds the system has been up.
The second number is how much of that time the machine has spent idle, in seconds.
# cat /proc/avalanche/avsar_modem_stats - display DSL modem stats
# iptables -L -n - display Iptables firewall rules
# ls /proc - see what commands are available in directories (proc in this case)