network speed:

yum install mtr
mtr -rw ip/domain

mtr -rw example.com

HDD:

df -h

RAM:

free -m

ps -A --sort -rss -o comm,pmem,rss
cat /proc/meminfo

CPU:

ps aux | sort -rk 3,3 | head -n 11
iostat 1 10

cat /proc/cpuinfo

version linux:

cat /proc/version