Raspberry pi, streamer + crontab + dropbox = catCamera, does not work!

Question

I wrote a bash script that uses the dropbox app as per RaspiTV. I am using a standard USB webcam and streamer to capture videos of my cat when I am away from home with the hope that these can be uploaded to my dropbox account.

the script that does this and works just fine when run manually is:

#!/bin/bash
streamer -t 0:0:15 -c /dev/video0 -f rgb24 -r 3 -o /home/pi/Downloads/$(date +%m%d_%H%M%S).avi
#echo
fn=`echo $(ls *.avi -t | head -n1)`
echo $fn
/home/pi/Dropbox-Uploader/./dropbox_uploader.sh upload $fn /catcamFolder

Where catcamFolder is my folder on Dropbox where the .avi files are deposited.

When I run my script manually from command line such as: ./myscript.sh, it runs beautifully and I have the video file depo'd in my dropbox.

However, when I try to cron it using the following crontab -e script, nothing happens, the file is neither generated not deposited in dropbox:

1,15,30,34,45 7-21 * * * /home/pi/Downloads/myscript.sh

So... this crontab line runs myscript.sh at minute 1,15,34,45 from 7am-9pm every day.

What am I doing wrong that the script doesn't run through cron but runs fine by itself? I hope I get help so that I can keep an eye on my feline friend!

By the way, the line of bash script: fn=echo $(ls *.avi -t | head -n1) provides the name of the most recent .avi file. This bit of useful information was from another SE

Answer 1

The following call contains a relative path *:

fn=`echo $(ls *.avi -t | head -n1)`

Use absolute paths:

fn=`echo $(ls /home/pi/Downloads/*.avi -t | head -n1)`

The script will not work even interactively if your current directory is not /home/pi/Downloads.

---

Other remarks:

• in this case the above will work, but generally you shouldn't parse the output of ls at all (read this).

• if you decide to parse ls you should at least quote fn variable in the call:

  /home/pi/Dropbox-Uploader/./dropbox_uploader.sh upload "$fn" /catcamFolder
  

  Again: it's not a direct reason for the problem, but the script will break if files contained spaces.

• echo is superfluous in the following assignment:

  fn=`echo $(ls *.avi -t | head -n1)`
  

  It is the same as:

  fn=$(ls *.avi -t | head -n1)