Powerful Commands for Linux Performance Monitoring.

• htop – Linux Process Monitoring
  Similar to top but user friendly interface to manage process,shortcut keys,vertical and horizontal view of the processes and much more.
• iostat – Input/Output Statistics
  Trace storage device performance issues including devices, local disks, remote disks such as NFS.
• iptraf – Real Time IP LAN Monitoring
  Collects a variety of information such as IP traffic monitor that passes over the network, including TCP flag information, ICMP details, TCP/UDP traffic breakdowns, TCP connection packet and byne counts. It also gathers information of general and detaled interface statistics of TCP, UDP, IP, ICMP, non-IP, IP checksum errors, interface activity etc.
• nethogs – Monitor Per Process Network Bandwidth
  Keeps a tab on each process network activity on your system. It also keeps a track of real time network traffic bandwidth used by each program or application.
• iftop – Network Bandwidth Monitoring
  iftop is a ‘top’ family tool that monitor a selected interface and displays a current bandwidth usage between two hosts.