Commands by ppq (2)

  • Remove specific versions of old kernels (Ubuntu/Debian)

    If, for example, you want to remove all kernels and headers but the last three versions, you can't use one of that magic all-in-one "remove old stuff" commands. With this simple but elegant command you can remove a range of versions, or a list of versions with e.g. {14,16,20}. Show Sample Output


    1
    apt purge linux*{14..18}*
    ppq · 2016-04-20 07:44:55 0
  • Burn a simple DVD-Video without menu using any given video file

    This is the fastest way to burn a DVD-Video from the command line. Dependencies: libav-tools dvdauthor growisofs The first command: avconv -i input.avi -target pal-dvd dvd.mpg converts any given video file avconv can handle into MPEG2-PS (6 Mbit/s) with AC3 audio (448 kbit/s). If your distribution is not up to date, just use ffmpeg - the syntax is the same. Hint: If you want to create an NTSC DVD, type ntsc-dvd instead ;-) The second command: echo PAL > ~/.config/video_format sets PAL as your default video format. This is a workaround for an old dvdauthor bug. If you want NTSC, guess what? Type NTSC instead! The third command: dvdauthor -o dvd/ -t dvd.mpg creates .VOB files and adds them to the dvd/ folder. You don't have to create this folder yourself. You can add as many titles as you like, just keep in mind that there's a maximum of 4482 MiB (4.37 GiB) for normal DVDs. The fourth command: dvdauthor -o dvd/ -T finishes the DVD-Video. Now you can burn your DVD using growisofs: growisofs -Z /dev/dvd -dvd-video dvd/ Sources: manpages http://tuxicity.wordpress.com/2006/12/01/avi-to-dvd-with-ffmpeg-and-dvdauthor/


    0
    avconv -i input.avi -target pal-dvd dvd.mpg && echo PAL > ~/.config/video_format && dvdauthor -o dvd/ -t dvd.mpg && dvdauthor -o dvd/ -T && growisofs -Z /dev/dvd -dvd-video dvd/
    ppq · 2012-09-09 20:56:54 0

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Run the last command as root
Useful when you forget to use sudo for a command. "!!" grabs the last run command.

Get first Git commit hash
git log --format=%H | tail -1 doesn't work anymore

Function that outputs dots every second until command completes
Very useful in shell scripts because you can run a task nicely in the background using job-control and output progress until it completes. Here's an example of how I use it in backup scripts to run gpg in the background to encrypt an archive file (which I create in this same way). $! is the process ID of the last run command, which is saved here as the variable PI, then sleeper is called with the process id of the gpg task (PI), and sleeper is also specified to output : instead of the default . every 3 seconds instead of the default 1. So a shorter version would be sleeper $!; The wait is also used here, though it may not be needed on your system. $ echo ">>> ENCRYPTING SQL BACKUP" $ gpg --output archive.tgz.asc --encrypt archive.tgz 1>/dev/null & $ PI=$!; sleeper $PI ":" 3; wait $PI && rm archive.tgz &>/dev/null Previously to get around the $! not always being available, I would instead check for the existance of the process ID by checking if the directory /proc/$PID existed, but not everyone uses proc anymore. That version is currently the one at http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html but I plan on upgrading to this new version soon.

finds the c files with lines containing 'mcs', in the folders under the current folder

Display a list of all PHP classes that are called statically
Searches all .php files for a static instantiation of a class and displays the class names along with their frequencies.

Console clock
Shows a simple clock in the console -t param removes the watch header Ctrl-c to exit

Split a file one piece at a time, when using the split command isn't an option (not enough disk space)
bs = buffer size (basically defined the size of a "unit" used by count and skip) count = the number of buffers to copy (16m * 32 = 1/2 gig) skip = (32 * 2) we are grabbing piece 3...which means 2 have already been written so skip (2 * count) i will edit this later if i can to make this all more understandable

Download all mp3's listed in an html page

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"

Create a large test file (taking no space).

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