JDPFu.com 2025

Below is a script that will playback a group of audio files in order, grouped by day. Suppose you have files named like this

File-1×01.mp3

   .

File-1×12.mp3

File-2×01.mp3

   .

File-2×10.mp3

File-3×01.mp3

   .

File-3×10.mp3

   .

File-7×10.mp3

File-8×01.mp3

   .

File-8×10.mp3

and want to play group Yx1-6 followed by group Yx6-12 daily. If you just wanted to do this for 1 set of files, it would be easier to just use `at` to play them. But you might have 10-50 files like this and only want to worry about setting up playback once a month or so.

Here’s the bonehead shell script that I’m using to accomplish this.

#!/bin/sh


	
Program to playback  audio tapes in order
	
based on day of the month – best to start on 1st.

#
	
It isn’t pretty, but it works assuming you want to cover
	
half a lesson each day. The filenames look like this:
	

	
File-8×10.mp3

MP=/usr/bin/mplayer

DIR=/Data/Audio/Session1

FILE_ROOT=File

DATE=`date “+%d”` # Returns the day of the month

ODD=`expr $DATE % 2`

START_GRP=`expr 1 + $DATE / 2` # pick a start date

ODD_START_NO=“01 02 03 04 05 06”

EVEN_START_NO=“06 07 08 09 10 11 12”

FILE_EXT=mp3

	
Changing the 0 to a 1 will toggle which group of files to begin

if [ $ODD = “0” ] ; then

  START_NO=$ODD_START_NO

else

  START_NO=$EVEN_START_NO

fi

for count in $START_NO; do

   afile=“$DIR/$FILE_ROOT-${START_GRP}x$count.$FILE_EXT”

   if [ -f “$afile” ] ; then

      $MP “$afile”

   else

      echo " File missing: $afile"

 fi

done

exit;

So, it isn’t very pretty and it is dependent on starting the script on the first of the month. Since today happens to be Oct 31 and I just finished the first group, I tweaked the EVEN/ODD and date modulus to jump 1 day ahead tomorrow – Nov 1. It will fail when a month roles over to the next month.

A fix to that problem would be to convert the date into a Julian day of the year, DOTY, and subtract off the current DOTY from the starting date. Check out date "+%j" for more on Julian dates. Of course, then it will break at the new year, so perhaps getting the number of seconds since epoch and performing calculations based on that would be even better? Even that method will break in 2038. At some point, the complexity outweighs the difficulty to implement.

Lastly, we need to setup crontab to run the script, playing the file.

1 6 * * * /home/jp/bin/daily_audio.sh

Enjoy.