Cron doesn't send e-mail with output of command (works from shell prompt)

Question

CentOS 5.5 x86_64

Trying to e-mail a periodic system update with the output of a system temperatures command:

hpasmcli -s "show temp"

Outputs something like:

Sensor   Location              Temp       Threshold
------   --------              ----       ---------
#1        AMBIENT              21C/69F    42C/107F
...

So, I script this:

#!/bin/bash
hpasmcli -s "show temp" > /tmp/monitorTemp.log &
wait
mail -s "temperature" me@mydomain.com < /tmp/monitorTemp.log
rm -f /tmp/monitorTemp.log

Set to run every hour in cron

* */1 * * * /root/monitorTemp.sh

I receive the e-mail, but it's empty. However, if I simply run it from the command line ./monitorTemp.sh it sends me the e-mail with command output included!

What am I missing?

Answer 1

Try changing this:

hpasmcli -s "show temp" > /tmp/monitorTemp.log &
wait

to:

cd /path/to/hpasmcli
./hpasmcli -s "show temp" > /tmp/monitorTemp.log

When running from cron, you don't have the same PATH as when running logged in normally, that's something worth to keeping in mind. You can also change the PATH before

PATH=$PATH:/path/to/hpasmcli
hpasmcli -s "show temp" > /tmp/monitorTemp.log

or something similar. You can get the /path/to/hpasmcli by doing which hpasmcli from your regular command prompt.

EDIT: As Dennis notes in the comments, for simple scripts like this one, there's no need to cd or setup PATH, this would be just fine:

/path/to/hpasmcli -s "show temp" > /tmp/monitorTemp.log

Answer 2

You can also set a PATH explicitly in your crontab.

eg. PATH=/usr/bin:/usr/sbin:/path/to/executable:. * */1 * * * /root/monitorTemp.sh

But I agree that explicitly setting path in scripts is probably a better solution for one offs.