Commands by Dhinesh (13)

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Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.

Configure a serial line device so you can evaluate it with a shell script
I had a hard time in finding the correct settings to get reasonable output from a coin selector which sends its data over a serial line. In the end, minicom came to the rescue and pointed me on the right track. So, if you need to do something similar, these settings may help you. Replace ttyUSB0 with your device file, 9600 with your baud rate, 5 with your read timeout (10ths of a second), and 1 with the minimum numbers of characters you want to read. You can then open the device file like you are used to do, example: $ DATA="`xxd -ps -l 5 \"$DEV\"`"

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.

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"

pretend to be busy in office to enjoy a cup of coffee
Create a progress dialog with custom title and text using zenity.

New files from parts of current buffer
On command mode in Vim you can save parts of the current buffer in another file. * The 'n' value represents the first line of the new file. * The 'm' value represents the last line of the new file. * newfile.txt is the newfile. The results are similar to this command in perl: $ perl -ne 'print if n..m' in.sql > out.sql

Define an alias with a correct completion
In Bash, when defining an alias, one usually loses the completion related to the function used in that alias (that completion is usually defined in /etc/bash_completion using the complete builtin). It's easy to reuse the work done for that completion in order to have smart completion for our alias. That's what is done by this command line (that's only an example but it may be very easy to reuse). Note 1 : You can use given command line in a loop "for old in apt-get apt-cache" if you want to define aliases like that for many commands. Note 2 : You can put the output of the command directly in your .bashrc file (after the ". /etc/bash_completion") to always have the alias and its completion

move a lot of files over ssh
copy files to a ssh server with gzip compression

List the size (in human readable form) of all sub folders from the current location
Simple and easy to remember. -h is human, -d1 = depth 1. disk usage, human, depth 1

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"


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