Bash script Question while loop

glennph93 · 12-29-2006, 06:15 PM

Hi all

This is probably an easy question, but for some reason I can't figure out why my loop ends doing only one task.

Code:

#!/bin/bash
#used to create playable podcast files on my sony mp3 player
#jk 12-29-06


# datadir is the directory where you want altered podcasts saved to:
datadir=48k

# create datadir if necessary:
mkdir -p $datadir

while read podcast
	do
		podcast48k=48k$podcast
		/usr/bin/ffmpeg -i $podcast -ab 48 -ac 2 -ar 44100 -acodec mp3 $datadir/$podcast48k &> /dev/null
	done< podcast.m3u

####wrote the below to test what i think should happen and it does what i think####
#while read podcast
#	do
#		podcast48k=48k$podcast
#		echo $podcast
#		echo $podcast48k
#		sleep 2
#	done< podcast.m3u

exit

I'm using bashpodder to get my podcast, which creates a simple playlist named podcast.m3u. Then I need to convert the files into something my sony mp3 player can read(mainly 44100 sample rate). I'm going to run the above to do that, but it ends after 1 line of the .m3u file. Any help would be appreciated

Thanks John

PTrenholme · 12-29-2006, 08:44 PM

You seem to be throwing away all messages from ffmpeg. Try it without the &>/dev/null to see if you might be getting an error return that's aborting your loop.

It's always a "good thing" to check after running a command to see if it has returned an error code.

<aside>
What's the point of defining datadir if you hard-code 48k in your output specification?
</aside>

glennph93 · 12-29-2006, 10:00 PM

Thanks for responding,

I tried to do it with out &>/dev/null prior to adding it same result(i thought before the output was the problem so I added &>/dev/null).

I guess I could take datadir(!!oops i get it i corrected the code) out but I wasn't sure it would create it just by my hardcode.

glennph93 · 12-30-2006, 10:05 AM

Well I solved my problem by going this route.

Code:

for podcast in `cat podcast.m3u`

	do
		podcast48k=48k$podcast
		/usr/bin/ffmpeg -i $podcast -ab 48 -ac 2 -ar 44100 -acodec mp3 $datadir/$podcast48k &> /dev/null
	done

not really satisfied, but it works.

Thanks John

gorbeia · 02-15-2007, 09:36 AM

The problem here is that ffmpeg is reading the standard input. This shold solve the problem:

Code:

while read podcast
do
  podcast48k=48k$podcast
  /usr/bin/ffmpeg -i $podcast -ab 48 -ac 2 -ar 44100 -acodec mp3 $datadir/$podcast48k < /dev/null
done< podcast.m3u

glennph93 · 02-15-2007, 11:51 AM

Thanks gorbeia, I haven't tried it yet but it makes sense to me that it will work.

Brotherred · 05-25-2007, 03:27 PM

Hello I run pcLos and I want to run a bash script to download my poddcasts regardless of what ever user is logged in. I am most likely to use Kpodder but who knows? Would I use cron? How do I do it?