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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

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Maintained by Jon H.

Site originally by David Winterbottom (user root).

Psst. Open beta.

Wow, didn't really expect you to read this far down. The latest iteration of the site is in open beta. It's a gentle open beta-- not in prime-time just yet. It's being hosted over at UpGuard (link) and you are more than welcome to give it a shot. Couple things:

  • » The open beta is running a copy of the database that will not carry over to the final version. Don't post anything you don't mind losing.
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Your feedback is appreciated via the form on the beta page. Thanks! -Jon & CLFU Team

Commands tagged Network from sorted by
Terminal - Commands tagged Network - 121 results
ifconfig | grep "0xffffffff" | awk '{ print $2 }' | xargs -n 1 ifconfig em0 delete
2009-08-04 05:18:36
User: vwal
Functions: awk grep ifconfig xargs

The example command deletes all aliases for network interface 'em0' assuming that the aliases have netmask of and the master IP has some other netmask (such as See here -> http://my.galagzee.com/2009/07/22/deleting-all-network-interface-aliases/ for more on the rationale of this command.

ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1'
2009-07-31 09:49:17
User: sneaker
Functions: ifconfig perl

works on Linux and Solaris. I think it will work on nearly all *nix-es

curl -s checkip.dyndns.org | grep -Eo '[0-9\.]+'
2009-05-21 16:12:21
User: haivu
Functions: grep

The curl command retrieve the HTML text containing the IP address. The grep command picks out the IP address from that HTML text.

lsof -i | grep -i estab
python -c "import socket; print '\n'.join(socket.gethostbyname_ex(socket.gethostname())[2])"
2009-04-30 16:10:43
User: haivu
Functions: python
Tags: Network python

The socket.gethostname() call returns the host name of the computer. The socket.gethostbyname_ex() call returns a list of three items: The host name, the list of aliases for this host, and a list of IP addresses. Recall that Python?s array starts with index 0, the socket.gethostbyname_ex(?)[2] expression refers to the list of IP addresses. Finally, the print statement prints out the IP addresses, one per line.

for i in /sys/class/net/*; do e=`basename $i`; echo "# $e"; sudo ethtool $e | grep -E "Link|Speed" ; done
2009-04-25 14:32:08
User: hank
Functions: echo grep sudo
Tags: Network Linux

Basically an improvement on an earlier ethtool command line.

lsof -i
/sbin/ifconfig -a | awk '/(cast)/ { print $2 }' | cut -d':' -f2 | head -1
mtr --report --report-cycles 10 www.google.com > google_net_report.txt
2009-04-10 07:57:44
User: CafeNinja
Tags: Network

The report mode of mtr produces a text formated result of the mtr run using the number of ping cycles stated by the command. This text file could then be attached to an email with ease.

I use this also without the ">" portion when writing email from within mutt using VI from the command mode with ":r !mtr --report --report-cycles 10

sudo tcpdump -i en1 -n -s 0 -w - | grep -a -o -E "Host\: .*|GET \/.*"
2009-04-04 01:41:48
User: peterc
Functions: grep sudo tcpdump

Replace "en1" with your network interface (on OS X, usually en0, en1, eth0, etc..)

arp -s $(route -n | awk '/^ {print $2}') \ $(arp -n | grep `route -n | awk '/^ {print $2}'`| awk '{print $3}')
alias tproxy='ssh -ND 8118 user@server&; export LD_PRELOAD="/usr/lib/libtsocks.so"'
/usr/sbin/arp -i eth0 | awk '{print $3}' | sed 1d
ping -i 60 -a IP_address
2009-03-04 06:21:22
User: haivu
Functions: ping
Tags: Network

Waiting for your server to finish rebooting? Issue the command above and you will hear a beep when it comes online. The -i 60 flag tells ping to wait for 60 seconds between ping, putting less strain on your system. Vary it to your need. The -a flag tells ping to include an audible bell in the output when a package is received (that is, when your server comes online).

ping -c 10 hostname
2009-03-04 06:14:52
User: haivu
Functions: ping
Tags: Network

On Linux and Mac systems (I have not tested with other Unix systems), the ping command will keep on pinging until the user interrupts it with Ctrl+C. On Windows system, ping will execute for a number of times then quit. The -c flag on Linux and Mac will make this happen

nc -l -p 2000 -e /bin/bash
2009-03-02 15:58:25
User: prayer
Tags: Network netcat

To connect to the shell run:

nc server.example.org 2000
nc -l -p 2000 < song.mp3
nc -l -p 2000 -c "nc example.org 3000"
2009-03-01 21:28:39
User: prayer
Tags: Network netcat

Redirect the local port 2000 to the remote port 3000. The same but UDP:

nc -u -l -p 2000 -c "nc -u example.org 3000"

It may be used to "convert" TCP client to UDP server (or viceversa):

nc -l -p 2000 -c "nc -u example.org 3000"
mii-tool [if]
nmap -sS -P0 -sV -O <target>
2009-02-18 07:32:03
User: starchox
Tags: Network net

Where < target > may be a single IP, a hostname or a subnet

-sS TCP SYN scanning (also known as half-open, or stealth scanning)

-P0 option allows you to switch off ICMP pings.

-sV option enables version detection

-O flag attempt to identify the remote operating system

Other option:

-A option enables both OS fingerprinting and version detection

-v use -v twice for more verbosity.

nmap -sS -P0 -A -v < target >
vncserver -nohttpd -name hidef-server -depth 24 -geometry 1440x900
2009-02-17 17:50:33
User: starchox
Tags: Network , net

-nohttpd don't run mini-httpd if VNC java applet is found

-name change the name of the desktop, it's passed to xstartup script via $VNCDESKTOP, run different set of apps acording the name.

-depth pixel depth in bits of the desktop, default is 16

-geometry size of the desktop, default is 1024x768