Commands using nice (7)

  • To rip DVD movie to ogg format using ffmpeg, follow these steps. 1) find the vob files on the mounted video DVD in VIDEO_TS that stores the movie itself. There would be a few other VOB files that stores splash screen or special features, the vob files for the movie itself can be identified by its superior size. You can verify these vob files by playing them directly with a player (e.g. mplayer) 2) concatenate all such vob files, pipe to ffmpeg 3) calculate the video size and crop size. The ogg video size must be multiple of 16 on both width and height, this is inherit limitation of theora codec. In my case I took 512x384. The -vcodec parameter is necessary because ffmpeg doesn't support theora by itself. -acodec is necessary otherwise ffmpeg uses flac by default.


    5
    cat VIDEO_TS/VTS_01_[1234].VOB | nice ffmpeg -i - -s 512x384 -vcodec libtheora -acodec libvorbis ~/Videos/dvd_rip.ogg
    zhangweiwu · 2010-09-14 14:45:27 26
  • This takes the stream created by apache requests containing jsp and funnels them to another server. I'm using this for simulating real time traffic. The nice command gives ssh maximum CPU cycles, awk & grep strip out everything served by apache. Putting parallel on curl is important because curl is synchronous and waits for the response. Yes, I thought about using wget but it didn't seem any easier. Also, if you figure out how to run this in the background let me know. Every time I background it it stops. If you have multiple front end servers just run multiple instances of this.


    3
    nice -n -20 ssh SOURCE_SERVER "tail -f /var/log/httpd/access.log " | awk '{print $7}' | grep jsp | parallel 'curl TARGET_SERVER{} 2>&1 /dev/null'
    dennisfaust · 2011-05-09 19:32:40 5
  • Check out the usage of 'trap', you may not have seen this one much. This command provides a way to schedule commands at certain times by running them after sleep finishes sleeping. In the example 'sleep 2h' sleeps for 2 hours. What is cool about this command is that it uses the 'trap' builtin bash command to remove the SIGHUP trap that normally exits all processes started by the shell upon logout. The 'trap 1' command then restores the normal SIGHUP behaviour. It also uses the 'nice -n 19' command which causes the sleep process to be run with minimal CPU. Further, it runs all the commands within the 2nd parentheses in the background. This is sweet cuz you can fire off as many of these as you want. Very helpful for shell scripts.


    2
    ( trap '' 1; ( nice -n 19 sleep 2h && command rm -v -rf /garbage/ &>/dev/null && trap 1 ) & )
    AskApache · 2009-10-10 04:43:44 7
  • This command will nicely dump a filesystem to STDOUT, compress it, encrypt it with the gpg key of your choice, throttle the the data stream to 60kb/s and finally use ssh to copy the contents to an image on a remote machine. Show Sample Output


    2
    nice -n19 dump -0af - /<filesystem> -z9|gpg -e -r <gpg key id>|cstream -v 1 -t 60k|ssh <user@host> "cat > backup.img"
    din7 · 2009-10-29 18:27:25 5
  • This is a simple command which makes electricsheep render directly to your background


    0
    nice -n 5 electricsheep -window-id `xwininfo -root|head -n 2|grep xwininfo|cut -c 22-26`
    kbaegis · 2011-02-14 03:58:58 5

  • 0
    find /logdir -type f -mtime +7 -print0 | xargs -0 -n 1 nice -n 20 bzip2 -9
    rootninja · 2014-02-12 19:35:09 7

  • -6
    nice -n0 ls | mpg321 -@- &
    kev · 2011-07-10 11:50:46 8

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Run a bash script in debug mode, show output and save it on a file

recurisvely md5 all files in a tree
Found this little gem here: http://info.michael-simons.eu/2008/10/25/recursively-md5sum-all-files-in-a-directory-tree/

tail, with specific pattern colored

Help shell find freshly installed applications (re: PATH)
Immediately after installing things into your PATH (e.g. under /usr/bin), currently open shells cannot find them ("zsh: command not found"). Use rehash to get the shell to rescan available executables.

Make alias pemanent fast
Simple function to permanently add an alias to your profile. Tested on bash and Ksh, bash version above. Here is the ksh version: PERMA () { print "$@" >> ~/.profile; } Sample usage: PERMA alias la='ls -a'

Scan your LAN for unauthorized IPs
populate the auth.hosts file with a list of IP addresses that are authorized to be in use and when you run this command it will return the addresses that are pingable and not in the authorized list. Can be combined with the "Command line Twitter" command to tweet unauthorized access.

Compare copies of a file with md5
I had the problem that the Md5 Sum of a file changed after copying it to my external disk. This unhandy command helped me to fix the problem.

gag version of current date

Install pip with Proxy
Installs pip packages defining a proxy

Rename files in batch


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