commandlinefu.com is the place to record those command-line gems that you return to again and again.
Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.
If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/
You can sign-in using OpenID credentials, or register a traditional username and password.
First-time OpenID users will be automatically assigned a username which can be changed after signing in.
Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
Subscribe to the feed for:
The files are automatically uncompressed when they reach the destination machine. This is a fast way to backup your server to your local computer while it's running (shutting down services is recommended).
A file named "exclude.txt" is needed at /tmp/ containing the following :
connect to it with any network command (including web browser - if you don't mind weird formatting)
nc 127.0.0.1 9876
The sed script ensures that the "random" MAC address is unicast (bit 0 of first byte == 0) and local (bit 1 of first byte == 1)
Using netcat (nc)
25 can be replaced with the friendly value (smtp). Check error code for result or use -v option to echo output
nc -z localhost smtp && echo open || echo closed
nc -zv host protocol
netstat will list all open ports on the system, unix sockets, tcp sockets and udp sockets. the t flag limits to tcp ports the l flag limits to listening ports and the n flag disables the translation of port to service ( ie :25 displayed instead of :smtp ). then grep for the port you are interested in preceeded by a colon.
Check trough unix sockets if tcp port is open or close
Gets your IP address and has a shorter URL.
No junk, no pipe, one command, no subcommand - KISS
Why use many different utilities all piped together, when you only need two?
Nethogs groups bandwidth by process.
Requires software found at: http://lpccomp.bc.ca/remserial/
Remote [A] (with physical serial port connected to device)
./remserial -d -p 23000 -s "115200 raw" /dev/ttyS0 &
Local [B] (running the program that needs to connect to serial device)
Create a SSH tunnel to the remote server:
ssh -N -L 23000:localhost:23000 user@hostwithphysicalserialport
Use the locally tunnelled port to connect the local virtual serial port to the remote real physical port:
./remserial -d -r localhost -p 23000 -l /dev/remser1 /dev/ptmx &
Example: Running minicom on machine B using serial /dev/remser1 will actually connect you to whatever device is plugged into machine A's serial port /dev/ttyS0.
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.
Replace 500ms by the desired delay.
To remove it: sudo tc qdisc del dev lo root netem delay 500ms