Commands by kostis (3)

  • Converts all pngs in a folder to webp using all available cores

    As an alternative to the above command, this one ditches the unnecessary and complicated for loop in favor of a way faster multi-core approach for a task that's more CPU than I/O intensive, making it a perfect suite for GNU parallel


    4
    parallel cwebp -q 80 {} -o {.}.webp ::: *.png
    kostis · 2018-12-07 23:37:24 1
  • quick integer CPU benchmark

    You could have that little benchmark run on all cores in parallel, as a multi-core benchmark or stress test First find the number of cores, then have parallel iterate over that in, well, parallel Show Sample Output


    -1
    time cat /proc/cpuinfo |grep proc|wc -l|xargs seq|parallel -N 0 echo "2^2^20" '|' bc
    kostis · 2018-12-06 05:36:55 0
  • small CPU benchmark with PI, bc and time.

    Broken in two parts, first get the number of cores with cat /proc/cpuinfo |grep proc|wc -l and create a integer sequence with that number (xargs seq), then have GNU parallel loop that many times over the given command. Cheers! Show Sample Output


    -2
    time cat /proc/cpuinfo |grep proc|wc -l|xargs seq|parallel -N 0 echo "scale=4000\; a\(1\)\*4" '|' bc -l
    kostis · 2018-12-06 05:15:24 2

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Limit bandwidth usage by any program
Trickle is a voluntary, cooperative bandwidth shaper. it works entirely in userland and is very easy to use. The most simple application is to limit the bandwidth usage of programs.

Runs a command without hangups.
The improvement is that you can re-attach to the screen at a later point.

View the newest xkcd comic.

Create a mirror of a local folder, on a remote server
Create a exact mirror of the local folder "/root/files", on remote server 'remote_server' using SSH command (listening on port 22) (all files & folders on destination server/folder will be deleted)

RTFM function
Same as the other rtfm's, but using the more correct xdg-open instead of $BROWSER. I can't find a way to open info only if the term exists, so it stays out of my version.

Find the package that installed a command

Extract audio stream from an video file using mencoder
This command extracts the audio stream of the video in $file and stores it in a file where the original suffix is changed to .mp3

Schedule a script or command in x num hours, silently run in the background even if logged out
doesn't require "at", change the "2h" to whatever you want... (deafult unit for sleep is seconds)

Steve Reich - Piano Phase; interpreter: Bourne-Again Shell.
The Piano Phase piece, by Steve Reich is a minimalist composition which is played on two pianos played at slightly different tempos, a task that's very difficult to accomplish by human players. The auditive effects produced by the cell displacement produce beautiful patterns. See https://en.wikipedia.org/wiki/Piano_Phase . My rendered version: https://ydor.org/SteveReich/piano_phase.mp3 Requires sox to be installed on the system. There are multiple videos on youtube showing different approaches and experiences to this interpretation. There is also a synthesized version. Even if Bash can behave as a powerful pianist, a simple threaded version leaves full room to several time glitches and even negative displacements, the same issues that human pianists experience when playing the piece. The older the computer, the better the chaos added to the result due to the CPU load. Apparently that's the reason Steve Reich composes pieces such as this. Without further ado, please give a warm welcome to the Bash minimalist player on synthesized two-threaded pianos. Please turn off your cellphones.

Reuse all parameter of the previous command line
!* is all of the arguments to the previous command rather than just the last one. This is useful in many situations. Here's a simple example: $ vi cd /stuff oops! [exit vi, twice] $ !* expands to: cd /stuff

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