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Running shell scripts with cron

I've been having a bit of trouble running a shell script with cron.
A friend of mine does a community radio show and the station has a live stream but no podcasts, so I've set up a script to record the stream and encode it as an mp3 while I'm away using mplayer and lame -that's what I'm trying to do anyway

Here's the script, but it doesn't seem to run- at least, I don't see any of the files it should be outputing, would they be in the cron.weekly directory (where I have the script) or in my home directory?

#This is a script to record 'The Unnamed Show'

#it will record the show from the live stream, then convert the output #to an MP3

#Finally, it will delete any files no longer required

HOME=/home/byron/

58 12 * fri root mplayer -dumpstream http://202.50.176.139:8000/listen.pls

02 2 * fri root killall mplayer

04 2 * fri root mplayer -ao pcm stream.dump

35 2 * fri root lame audiodump.wav The_Unnamed_Show.mp3

05 3 * fri root chmod 777 The_Unnamed_Show.mp3

30 3 * fri root rm stream.dump

31 3 * fri root rm dumpstream.wav

Quote:

Originally Posted by Lossenelin (Post 3695381)

In the cron script, you must provide full paths to all executables. This is because cron scripts don't have the same search path that a user shell has.

Also, you have to provide full paths to the data files. Setting:

Code:

HOME=/home/byron/

Means nothing in a cron script. It doesn't change the active directory or make the target files accessible.

I'm also not sure about writing each command in your crontab, which is what that looks like you're doing. The only time-sensitive part seems to be the dumpstream. So you could just have a file with something like

Code:

#!/bin/sh

cd dumpdir # this will hold for the duration of the script

mplayer -dumpstream http://202.50.176.139:8000/listen.pls

sleep 3840 # mplayer may have a flag to set duration

killall mplayer

mplayer -ao pcm stream.dump

lame audiodump.wav The_Unnamed_Show.mp3 # can mplayer pipe directly to lame here?

chmod 777 The_Unnamed_Show.mp3

rm stream.dump dumpstream.wav

and run that file as a cronjob at '58 12 * fri'. Also, you should probably not 'killall mplayer'. If you have multiple users running it, or a user running multiple instances, they'll all get whacked. Maybe 'kill $(pgrep -f 'mplayer -dumpstream http://202.50.176.139:8000/listen.pls'). You might also want to wrap the rm in a test to make sure The_Unnamed_Show.mp3 exists/was successfully created. If it wasn't, you can manually try again rather than having missed the show.

Also, while it may not be recommended, I run my cron scripts through a wrapper which then runs the scripts. This gives me the shell and environment I want. This is "Dillon's cron" on Slackware - other distros seem to use really weird crons. FWIW, the essentials of it are simply:

Code:

#!/bin/bash



export JSYSPREFIX="$HOME/sys"

export JBINDIR="$JSYSPREFIX/bin"

export JSCRIPTDIR="$JSYSPREFIX/sbin"

export JVARDIR="$JSYSPREFIX/var"



export PATH=$JSCRIPTDIR:$JBINDIR:/usr/local/bin:/usr/bin:/bin



if [[ $DEBUG ]]; then

    logfile=/dev/stderr

else

    logfile="$JVARDIR/log/cron.log"

fi



"$@" >> $logfile 2>&1



if (( $? == 0 )); then

    echo "`date`: cronwrap ran \"$@\"" >> $logfile

else

    echo "`date`: cronwrap failed to run \"$@\"" >> $logfile

fi

Then my crontab just takes the form of

Code:

10 01 * * * /home/j/sys/sbin/cronwrap foo

10 02 * * * /home/j/sys/sbin/cronwrap bar

10 03 * * * /home/j/sys/sbin/cronwrap baz

This may be really stupid in some way I'm not aware of and it's certainly not bulletproof, but 50-mile long cron lines running stuff as /bin/sh got to bugging me and it mostly Works For Me(tm).