Commands by jonty (6)

  • If you spend all day editing in vi then switching your fingers to Emacs mode just for the command line can be difficult. Use set -o vi in your bash shell and enjoy the power of a real editor.


    1
    set -o vi; ls -l jnuk<ESC>bCjunk
    jonty · 2009-02-05 22:58:51 1
  • Einstein's razor: As simple as possible, but not simpler. On the destination machine netcat listens on any port (1234 in the example) and sends anything it receives into a file or pipe. On the source machine a separate netcat takes input from a file or pipe and sends it over the network to the listener. This is great between machines on a LAN where you don't care about authentication, encryption, or compression and I would recommend it for being simpler than anything else in this situation. Over the internet you should use something with better security.


    3
    (on destination machine) nc -l 1234 > whatever; (on source machine) nc destination 1234 < whatever;
    jonty · 2009-02-05 21:35:08 1
  • At some point you want to know what packets are flowing on your network. Use tcpdump for this. The man page is obtuse, to say the least, so here are some simple commands to get you started. -n means show IP numbers and don't try to translate them to names. -l means write a line as soon as it is ready. -i eth0 means trace the packets flowing through the first ethernet interface. src or dst w.x.y.z traces only packets going to or from IP address w.x.y.z. port 80 traces only packets for HTTP. proto udp traces only packets for UDP protocol. Once you are happy with each option combine them with 'and' 'or' 'not' to get the effects you want.


    2
    tcpdump -nli eth0; tcpdump -nli eth0 src or dst w.x.y.z; tcpdump -nli eth0 port 80; tcpdump -nli eth0 proto udp
    jonty · 2009-02-05 17:41:55 1
  • If you are already running screen then you often want to start a command in a fresh window. You use this alias by typing 's whatever' from your command line and 'whatever' starts running in a new window. Good with interactive commands like info, vim, and nethack.


    19
    alias s='screen -X screen'; s top; s vi; s man ls;
    jonty · 2009-02-05 13:47:14 3
  • Fool date by setting the timezone out by 24 hours and you get yesterday's date. Try TZ=XYZ-24 to get tomorrow's date. I live in TZ=GMT0BST so you might need to shift the number 24 by the hours in your timezone.


    1
    TZ=XYZ24 date
    jonty · 2009-02-05 13:27:14 4
  • I find this handy for linking all the bin files in a package to /usr/bin or all the man files to /usr/share/man. You can replace * with */* to operate on all the files in subdirectories.


    0
    cd /this/directory; for f in *; do ln -s `pwd`/$f /that/directory; done
    jonty · 2009-02-05 13:21:16 1

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Check These Out

Draw kernel module dependancy graph.
parse "lsmod" output to "dot" format and pass it to "display". Without perl!

Kill most recently created process.
Kills the most recently created firefox process.

Watch Data Usage on eth0

which process has a port open

Force wrap all text to 80 columns in Vim
This is assuming that you're editing some file that has not been wrapped at 80 columns, and you want it to be wrapped. While in Vim, enter ex mode, and set the textwidth to 80 columns: $ :set textwidth=80 Then, press: $ gg to get to the top of the file, and: $ gqG to wrap every line from the top to the bottom of the file at 80 characters. Of course, this will lose any indentation blocks you've setup if typing up some source code, or doing type setting. You can make modifications to this command as needed, as 'gq' is the formatting command you want, then you could send the formatting to a specific line in the file, rather than to the end of the file. $ gq49G Will apply the format from your current cursor location to the 49th row. And so on.

Get the Nth argument of the last command (handling spaces correctly)
Bash's history expansion character, "!", has many features, including "!:" for choosing a specific argument (or range of arguments) from the history. The gist is any number after !: is the number of the argument you want, with !:1 being the first argument and !:0 being the command. See the sample output for a few examples. For full details search for "^HISTORY EXPANSION" in the bash(1) man page.    Note that this version improves on the previous function in that it handles arguments that include whitespace correctly.

Generate a sequence of numbers.

A function to find the newest file in a directory

Programmatic way to find and set your timezone
1. it find your public ip via ifconfig.io 2. than use this IP to request your timezone via worldtimeapi.org 3. and send it to the command timedatectl set-timezone

Testing php configuration
Run the function phpinfo() on the shell


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