Commands by penpen (13)

  • Today I learned that commandlinefu.com is not a alone in its conquest for further the knowledge about the command line. Allow me to introduce you to http://shell-fu.org/


    -9
    lynx http://shell-fu.org/
    penpen · 2009-08-20 11:47:35 2
  • Using DynDNS or a similar service not only allows access to your home machine from outside without needing to know what IP the ISP has assigned to it but it also comes in handy if you want to know your external IP address. The only purpose of the sed command is to remove the leading "host.na.me has address " part from the output. If you don't need to discard it you can simply use host $HOSTNAME


    1
    host $HOSTNAME|cut -d' ' -f4
    penpen · 2009-08-08 12:39:00 2
  • To change to $HOME in that manner you need to set a shell option. In zsh it is auto_cd, hence setopt -o auto_cd in bash4 it is autocd, hence shopt -s autocd What the option does is allow you to cd to a directory by just entering its name. This also works if the directory name is stored in a variable: www=/var/www/lighttpd; $www sends you to /var/www/lighttpd. CAUTION: If a command or function name identical to the directory name exists it takes precedence.


    2
    ~
    penpen · 2009-07-24 10:43:53 3
  • Depending on the installation only certain of these man pages are installed. 12 is left out on purpose because ISO/IEC 8859-12 does not exist. To also access those manpages that are not installed use opera (or any other browser that supports all the character sets involved) to display online versions of the manpages hosted at kernel.org: for i in $(seq 1 11) 13 14 15 16; do opera http://www.kernel.org/doc/man-pages/online/pages/man7/iso_8859-$i.7.html; done


    -2
    for i in $(seq 1 11) 13 14 15 16; do man iso-8859-$i; done
    penpen · 2009-03-31 19:40:15 1
  • Let me suggest using wget for obtaining the HTTP header only as the last resort because it generates considerable textual overhead. The first ellipsis of the sample output stands for Spider mode enabled. Check if remote file exists. --2009-03-31 20:42:46-- http://www.example.com/ Resolving www.example.com... 208.77.188.166 Connecting to www.example.com|208.77.188.166|:80... connected. HTTP request sent, awaiting response... and the second one looks for Length: 438 [text/html] Remote file exists and could contain further links, but recursion is disabled -- not retrieving. Show Sample Output


    7
    wget --server-response --spider http://www.example.com/
    penpen · 2009-03-31 18:49:14 6
  • Without the -dump option the header is displayed in lynx. You can also use w3m, the command then is w3m -dump_head http://www.example.com/ Show Sample Output


    -1
    lynx -dump -head http://www.example.com/
    penpen · 2009-03-31 18:41:36 1
  • In the above example 'muspi merol' (the output of the first rev command) is sent to stderr and 'lorem ipsum' (the output of the second rev command) is sent to stdout. rev reverse lines of a file or files. This use of tee allows testing if a program correctly handles its input without using files that hold the data. Show Sample Output


    2
    rev <<< 'lorem ipsum' | tee /dev/stderr | rev
    penpen · 2009-03-31 13:12:09 2
  • rot13 maps a..mn..z (A..MN..Z) to n..za..m (n..za..m) and so does this alias.


    10
    alias rot13="tr '[A-Za-z]' '[N-ZA-Mn-za-m]'"
    penpen · 2009-03-30 19:08:49 2
  • An improved version of http://www.commandlinefu.com/commands/view/1772/simple-countdown-from-a-given-date that uses Perl to pretty-print the output. Note that the GNU-style '--no-title' option has been replaced by its one-letter counterpart '-t'. Show Sample Output


    -2
    watch -tn1 'bc<<<"`date -d'\''friday 21:00'\'' +%s`-`date +%s`"|perl -ne'\''@p=gmtime($_);printf("%dd %02d:%02d:%02d\n",@p[7,2,1,0]);'\'
    penpen · 2009-03-29 19:53:36 3
  • Here $HOME/shots must exist and have appropriate access rights and sitecopy must be correctly set up to upload new screen shots to the remote site. Example .sitecopyrc (for illustration purposes only) site shots server ftp.example.com username user password antabakadesuka local /home/penpen/shots remote public_html/shots permissions ignore The command uses scrot to create a screen shot, moves it to the screen shot directory, uploads it using screen uses xsel to copy the URL to the paste buffer (so that you can paste it with a middle click) and finally uses feh to display a preview of the screen shot. Note that $BASE stands for the base URL for the screen shots on the remote server, replace it by the actual location; in the example http://www.example.com/~user/shots would be fitting. Assign this command to a key combination or an icon in whatever panel you use. Show Sample Output


    -1
    scrot -e 'mv $f \$HOME/shots/; sitecopy -u shots; echo "\$BASE/$f" | xsel -i; feh `xsel -o`'
    penpen · 2009-03-26 12:08:39 0
  • A web server using $HOME/public_html as user directory is required, $HOME/public_html/shots must exist and have appropriate access rights and $HOSTNAME must be known to and accessible from the outside world. The command uses scrot to create a screen shot, moves it to the screen shot directory, uses xsel to copy the URL to the paste buffer (so that you can paste it with a middle click) and finally uses feh to display a preview of the screen shot. Assign this command to a key combination or an icon in whatever panel you use.


    0
    scrot -e 'mv $f \$HOME/public_html/shots/; echo "http://\$HOSTNAME/~\$USER/shots/$f" | xsel -i; feh `xsel -o`'
    penpen · 2009-03-26 11:32:09 1
  • Have netcat listen on port 8000, point browser to http://localhost:8000/ and you see the information sent. netcat terminates as soon as your browser disconnects. I tested this command on my Fedora box but linuxrawkstar pointed out that he needs to use nc -l -p 8000 instead. This depends on the netcat version you use. The additional '-p' is required by GNU netcat that for example is used by Debian but not by the OpenBSD netcat port used by my Fedora system. Show Sample Output


    2
    nc -l 8000
    penpen · 2009-03-25 23:09:38 2
  • 'watch' repeatedly (default every 2 seconds, -n 1 => every second) runs a command (here ':', a shorthand for 'true'), displays the output (here nothing) and the date and time of the last run. I thought it to be obvious but it seemingly is not: to exit use Ctrl-C.


    -2
    watch -n 1 :
    penpen · 2009-03-25 23:00:28 1

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Capture video of a linux desktop
This is identical to the original command, but allows you to specify an offset if you have multiple monitors. In this case you'll record a 1366x768 window that's offset by 1366 pixels in the x axis and 0 pixels in the y axis. Note also that the -sameq option has been replaced by -qscale - at least in ffmpeg version 1.2.1 on Fedora 19.

Execute a sudo command remotely, without displaying the password
The ssh command alone will execute the sudo command remotely, but the password will be visible in the terminal as you type it. The two stty commands disable the terminal from echoing the password back to you, which makes the remote sudo act as it does locally.

Redirecting bash output into any X Window
bash output is inserted into the clipboard, then mousepad is started and the clipboard content is pasted. xsel and xdotool needs to be installed. Instead of the mousepad any other editor can be used. I've successfully tested the Sublime Text Editor and it opens a new tab for each new paste. Check Sample output for a usage example. This command is originated from here - http://goo.gl/0q9UT4

Command line calculator
This opens a python command line. You can use math and random and float-division is enabled (without appending .0 to integers). I just don't know how to specify a standard precision.

Watch the disk fill up with change highlighting
If you add the -d flag each difference in the command's output will be highlighted. I also monitor individual drives by adding them to df. Makes for a nice thin status line that I can shove to the bottom of the monitor.

A fun thing to do with ram is actually open it up and take a peek. This command will show you all the string (plain text) values in ram
cat? dd? RTFM

bash screensaver (scrolling ascii art with customizable message)
Displays a scrolling banner which loops until you hit Ctrl-C to terminate it. Make sure you finish your banner message with a space so it will loop nicely.

Get your mac to talk to you
Very entertaining when run on someone elses machine remotely ;)

find text in a file
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Download Youtube Playlist
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