commandlinefu.com is the place to record those command-line gems that you return to again and again.
You can sign-in using OpenID credentials, or register a traditional username and password.
Subscribe to the feed for:
A grep against ethtool to look for common errors and packet loss statistics which network drivers report in their private data, which is queried with ethool -S. This is the current grep used in xsos (https://github.com/ryran/xsos), which I originally contributed and has been improved by the community over time.
Wakes up a computer on your LAN with a Wake-On-LAN packet. MAC Address must match the NIC MAC, computer must have WOL enabled in the BIOS.
Shows which applications are making connections, and the addresses they're connecting to. Refreshes every 2 seconds (watch's default). Test on OSX, should work anywhere watch and lsof work.
Simple way to test if a port is available to the public. Run this command on the "server" and run a `telnet host-ip port-number` on the client. Test by sending strings to the server, which will be displayed in the server terminal.
This forces a bonded interface to switch to another slave in the bond as its active slave.
Super fast way to ftp/telnet/netcat/ssh/ping your loopback address for testing. The default route 0.0.0.0 is simply reduced to 0.
Disabling an interface's multicast filter is like disabling IGMP snooping on a switch. It is useful for testing and troubleshooting.
Real gurus don't need fancy tools like iftop or jnettop.
TCP Connect scanning for localhost and network 192.168.0.0/24
This option is much faster, as it checks only network nodes.
This option selects the listing of all Internet and x.25 (HP-UX) network files.
Check open TCP and UDP ports
While `lsof` will work, why not use the tool designed explicitly for this job?
(If not run as root, you will only see the names of PID you own)
shows opened ports on machine in continuous mode (refreshing every 10 sec)
This command only check the network connection from given eth. This is very useful if you are using more then one interface in your server or laptop.
see http://iptraf.seul.org/ for all kinds of documentation and screenshots
Sometimes, you don't really care about all the other information that ifconfig spits at you (however useful it may otherwise be). You just want an IP. This strips out all the crap and gives you exactly what you want.
on multihomed hosts, connected to several networks, could be usefull to know the source address (local ip address) used to reach the target host, this command does not require root priviledges.
The command use a TCP socket, if there is any error the command return an empty string, elsewhere return a valid ip address.