Commands by jonty (6)

  • Use vi commands to edit your command lines

    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 0
  • The simplest way to transport information over a network

    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 0
  • Getting started with tcpdump

    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 0
  • Start a new command in a new screen window

    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 1
  • Get me yesterday's date, even if today is 1-Mar-2008 and yesterday was 29-Feb-2008

    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 2
  • Link all the files in this directory to that directory

    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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Generate pretty secure random passwords
These are my favourite switches on pwgen: -B Don't include ambiguous characters in the password -n Include at least one number in the password -y Include at least one special symbol in the password -c Include at least one capital letter in the password It just works! Add a number to set password length, add another to set how many password to output. Example: pwgen -Bnyc 12 20 this will output 20 password of 12 chars length.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Print environment information.
Print environment (system) information using Perl.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Find all videos under current directory using MIME a.k.a not using extension
Videos are found using their MIME type. Thus no need to for an extension for the video file. This is a efficent version of "jnash" cmd (4086). Thanks for jnash. This cmd will only show video files while his cmd show files having "video" anywhere in path.

Rename files in batch

Google verbatim search on your terminal
Put it in your ~/.bashrc usage: google word1 word2 word3... google '"this search gets quoted"'

Download files linked in a RSS feed
The difference between the original version provided and this one is that this one works rather than outputting a wget error

Perform a reverse DNS lookup
Performs a reverse DNS lookup, variants include: $ nslookup 74.125.45.100 or: $ host 74.125.45.100

Create a pdf version of a manpage
Quick and dirty version. I made a version that checks if a manpage exists (but it's not a oneliner). You must have ps2pdf and of course Ghostscript installed in your box. Enhancements appreciated :-)

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