Inject a wav file in to a bash script

[Geoffrey]

I was wondering if was possible for a script to carry binary data, after a bit of searching I found the answer I was looking for, so made this example.

This script when run will extract the data to /tmp as chime.wav, then play the wav file as a sequence derived from the clock, to chime the hours.

Will work to chime the hours if run with Pschedule on the hour.

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#!/bin/bash

dd if="$0" of=/tmp/chime.wav bs=1 skip=131
hours=`date +"%-l"`
seq "$hours" | xargs -I{} aplay -q /tmp/chime.wav
exit;

In a working directory to build this place the chime.wav, then create a script with the above code and name it hour_chime

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cat chime.wav >> hour_chime
chmod +x hour_chime

Open a terminal in the working directory and paste the above code and run it, this injects the wav data in to the script.

The script is now a standalone not requiring any external file to function.

The important thing is the skip=? this needs to be precise else the extracted data will be corrupted.

[MochiMoppel]

[Geoffrey]

Your exit command bumps into the header of the wav file, which makes it "exitRIFFr", i.e. your script will not exit at this point. Make it exit; and change the skip value to 131. Still I can't see the usefulness of this exercise.

Ah! thanks, updated the first post, more a curiosity than a having a purpose for it, then you never know when it may find a purpose, just handy to know it can be done.

[MochiMoppel]

more a curiosity than a having a purpose for it

That's a valid reason
Let's try to make it a bit smarter. There is no need to extract the audio data into a tmp file. You can make the bash script "play itself". Create a script, let's call it header:

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#!/bin/bash
for ((c=1;c<=$(date +%l);c++));do dd if="$0"  bs=1 skip=90 | aplay; done
exit;

Make sure that the code has 90 characters, then combine header and chime.wav into a new script hourlychime.sh:

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cat header chime.wav > hourlychime.sh ; chmod +x  hourlychime.sh

Running hourlychime.sh will pipe the embedded audio data directly to aplay.

From here there is no limit to insanity: You can add a timer loop, so you won't need pschedule, you can pack more than one audio file into this script and even a player ... OK, I leave it to your curiosity.

[musher0]

Hi guys.

This technique is fascinating. Thanks to MochiMoppei for revisions and suggestions, and of
course to Geoffrey for initiating this thread.

Geoffrey, in the 1st line of your OP, you mention some research you did. Would you care to
share a few URLs about this technique for our benefit? TIA.

BTW, does this technique have a name?

BFN

[amigo]

Think about those *.run files -they are self-extracting scripts. The payload is a tarball or zipped file or whatever. Inside the script you have marker or other method to skip over the first script part, starting from the marker or offset and procesing that with whatever. You can use 'sed', 'head', 'cut', 'dd' or many other ways to skip to the payload and pipe that through whatever.

By appending such binary data, you can even have an 'exit' in your script to make sure the script will never get there.

[Geoffrey]

Let's try to make it a bit smarter. There is no need to extract the audio data into a tmp file. You can make the bash script "play itself"

Brilliant, that was my initial want, I just got lazy

share a few URLs about this technique for our benefit?
BTW, does this technique have a name?

https://stackoverflow.com/questions/276 ... fficiently

Think about those *.run files -they are self-extracting scripts.

That had crossed my mind during my search http://makeself.io/

[seaside]

Here's another way using tail.

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#!/bin/bash 
#chime.wav
#cat header chime.wav > hourlychime.sh ; chmod +x  hourlychime.sh
hours=`date +"%-l"` 
size=`stat -c %s chime.wav`
for (( i=1; i <= $hours; i++ )); do  tail -c $size hourlychime.sh | aplay;  done
exit;

Cheers,
s

[musher0]

Thanks, Geoffrey.

I wish you and all Puppyists a "Happy, Healthy and Successful New Year 2018"!

[vovchik]

Dear all,

Thanks for the examples. I learned something, as I usually from many posts on this forum. I wish you all a happy, prosperous and rewarding new year!

WIth kind regards,
vovchik

[Geoffrey]

Here's another way using tail.

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#!/bin/bash 
#chime.wav
#cat header chime.wav > hourlychime.sh ; chmod +x  hourlychime.sh
hours=`date +"%-l"` 
size=`stat -c %s chime.wav`
for (( i=1; i <= $hours; i++ )); do  tail -c $size hourlychime.sh | aplay;  done
exit;

Cheers,
s

That's good, here's a script to create the hourlychime.sh, just drag the wav file to it

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#!/bin/bash
SCRIPT="hourlychime.sh"
touch "$SCRIPT"
echo '#!/bin/bash
SCRIPT="$(readlink -e "$0")" 
for (( i=1; i <= `date +"%-l"`; i++ )); do  tail -c '$"`stat -c %s "$1"`"' "$SCRIPT" | aplay -q;  done
exit;' > "$SCRIPT"
cat "$1" >> "$SCRIPT" ; chmod +x  "$SCRIPT"

Happy new year

EDIT: Strangely enough this doesn't work from outside the directory it's in, I need to change directory in terminal for it to run, even if it's in /usr/bin

EDIT 2: fixed tail couldn't find the path

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SCRIPT="$(readlink -e "$0")"

[musher0]

Powerful stuff. Careful what you wish!!!
Someone could hide a < remove all command > in there!

[jamesbond]

Think about those *.run files -they are self-extracting scripts. The payload is a tarball or zipped file or whatever.

Here: http://makeself.io/
It's actually quite popular. VirtualBox generic Linux binaries for example are packaged with makeself. Nvidia proprietary drivers too.