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 1
  • 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 1
  • 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 1
  • 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 0
  • 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 0

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

  • -6
    nice -n0 ls | mpg321 -@- &
    kev · 2011-07-10 11:50:46 4

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Make ISO image of a folder
Create ISO image of a folder in Linux. You can assign label to ISO image and mount correctly with -allow-lowercase option.

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Displays the attempted user name, ip address, and time of SSH failed logins on Debian machines
A variation of a script I found on this site and then slimmed down to just use awk. It displays all users who have attempted to login to the box and failed using SSH. Pipe it to the sort command to see which usernames have the most failed logins.

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

GREP a PDF file.
PDF files are simultaneously wonderful and heinous. They are wonderful in being ubiquitous and mostly being cross platform. They are heinous in being very difficult to work with from the command line, search, grep, use only the text inside the PDF, or use outside of proprietary products. xpdf is a wonderful set of PDF tools. It is on many linux distros and can be installed on OS X. While primarily an open PDF viewer for X, xpdf has the tool "pdftotext" that can extract formated or unformatted text from inside a PDF that has text. This text stream can then be further processed by grep or other tool. The '-' after the file name directs output to stdout rather than to a text file the same name as the PDF. Make sure you use version 3.02 of pdftotext or later; earlier versions clipped lines. The lines extracted from a PDF without the "-layout" option are very long. More paragraphs. Use just to test that a pattern exists in the file. With "-layout" the output resembles the lines, but it is not perfect. xpdf is available open source at http://www.foolabs.com/xpdf/

pulsed terminal clock
hypnotizing pendulum

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Size(k) of directories(Biggest first)
somewhat faster version to see the size of our directories. Size will be in Kilo Bytes. to view smallest first change '-k1nr' to '-k1n'.

Cut/Copy everything arround brackets or parentheses on vim (in normal mode)
Put the cursor on either curly braces ( {, } ). Then press d% The d is delete command, and % is movement command that move the cursor to another matching parentheses (or curly braces in this case). This action will delete every character that was on the way of the movement (from the first curly braces to the second).


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