Cron job execute backup.bash - cron

Question

I wish to let cron executes delete_snapshot.bash, but when I try to create cron as below:
*/1 * * * * /var/www/mango_gis/delete_snapshot.bash >/dev/null
It didn't execute my script at all, because when I didn't see it delete the snapshot in the amazon cloud, and my script is already tested with bash, it work fine.
Here is my script as below:
#!/bin/bash
get()
{
local pos=$1
shift
eval 'echo ${'$pos'}';
}
length(){ echo $#; }
find_snapshots()
{
echo $(ec2-describe-snapshots | xargs -n1 basename);
}
snapshots=$(find_snapshots)
len=$(length $snapshots)
row_count=$(($len/6))
if(($row_count > 6)); then
delete_count=$(($row_count-6))
for (( i=1; i<=$delete_count; i++ )); do
ec2-delete-snapshot $(echo $(get $((2+$((6*$(($i-1)))))) $snapshots)) > /dev/null
done
fi
In above, I have found the problem is that I call one command of EC2 command.
I have tested to create one cron job to call this command is ec2-describe-snapshots, but it doesn't work.
Please advise...
Leakhina

Answer 1

you should add the program with which you want to process this file; something like:
*/1 * * * * /bin/bash /var/www/mango_gis/delete_snapshot.bash > /dev/null
using the full path is important, because you do not have the environment variables loaded when cron starts the process

Answer 2

thanks for your help so far.
Now I can catch it.
the problem is that cron not load the env variable so we just need to specify what we use to env variable while cron executing.
here is my test code for ec2 command as below:
export EC2_PRIVATE_KEY=/root/keys/pk-Q4NR5FGDTSWWK65EDSIDCBTEQWJ6G24V.pem
export EC2_CERT=/root/keys/cert-Q4NR5FGDTSWWK65EDSIDCBTEQWJ6G24V.pem
export JAVA_HOME=/usr/lib/jvm/java-6-sun/
export EC2_HOME_BIN=/usr/bin
echo "start ec2-describe-snapshots" >> /var/log/ec2-delete-snapshot.log
$EC2_HOME_BIN/ec2-describe-snapshots >> /var/log/ec2-delete-snapshot.log
echo "end it" >> /var/log/ec2-delete-snapshot.log