My Cheatsheet of Linux Status Commands | System Commands | Network Commands
sudo tail -f /var/log/httpd/error_log
display processors related statistics
display virtual memory statistics
display I/O statistics (2 s intervals)
systat -vmstat 1
BSD summary of system statistics (1 s intervals)
systat -tcp 1
BSD tcp connections (try also -ip)
systat -netstat 1
BSD active network connections
systat -ifstat 1
BSD network traffic through active interfaces
systat -iostat 1
BSD CPU and and disk throughput
tail -n 500 /var/log/messages
Last 500 kernel/syslog messages
System warnings messages see syslog.conf
netstat – The command netstat displays network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.
iostat – The command iostat report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS).
vmstat -3 – The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.
nmap – scan your server for open ports.
lsof – list open files, network connections and much more.
ntop – web based tool – ntop is the best tool to see network usage in a way similar to what top command does for processes i.e. it is network traffic monitoring software. You can see network status, protocol wise distribution of traffic for UDP, TCP, DNS, HTTP and other protocols.
Conky – Another good monitoring tool for the X Window System. It is highly configurable and is able to monitor many system variables including the status of the CPU, memory, swap space, disk storage, temperatures, processes, network interfaces, battery power, system messages, e-mail inboxes etc.
GKrellM – It can be used to monitor the status of CPUs, main memory, hard disks, network interfaces, local and remote mailboxes, and many other things.
vnstat – vnStat is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s).
htop – htop is an enhanced version of top, the interactive process viewer, which can display the list of processes in a tree form.
mtr – mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.