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Different output when run from crontab

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# 1  
Old 05-12-2011
Different output when run from crontab


I have a script which checks to see if an app is running and will restart it if it is not.

For some reason when I run it from the crontab it always says it is not running.

The script is as follows: -

# The following script will look for the PID of SickBeard and output the result

APPCHK=$(ps | grep $PROGRAM1 | grep -v "grep $PROGRAM1" | wc -l)

# The 'if' statement below checks to see if the process is running
# with the 'ps' command.  If the value is returned as a '0' then
# an email will be sent and the process will be safely restarted.

echo "Number of processes running =$APPCHK"

if [ $APPCHK = '0' ];


# Write datestamp & output to log file
echo "$(date +%c) $*" >> $LOG_DIR/$LOG_FILE
echo "$PROGRAM is not running">> $LOG_DIR/$LOG_FILE

# Send an email to advise SickBeard was down
echo "$PROGRAM is not running" | /opt/bin/nail -s "$LOG_FILE" -a $LOG_DIR/$LOG_FILE $SUPPORTSTAFF

# Start SickBeard
echo "$(date +%c) $*"
echo "Starting $PROGRAM"
/var/packages/sab2/target/utils/bin/python /volume1/@appstore/sickbeard/ --quiet &


# When Sickbeard is running write to log file to say all is fine
echo "$(date +%c) $*" >> $LOG_DIR/$LOG_FILE
echo "$PROGRAM is running">> $LOG_FILE
echo "No action taken...">> $LOG_FILE
echo "$PROGRAM is running"
echo "No action taken..."



The crontab entry is: -

#minute        hour        mday        month        wday        who        command
0        0        *        *        *        root        /usr/sbin/ntpdate -b
*/1        *        *        *        *        root        /volume1/@appstore/ >> /volume1/@appstore/log.txt 2>&1

The logic will always return APPCHK=0 when run from the crontab.

Any ideas?
# 2  
Old 05-12-2011
have you checked the mailbox for related errors while running this job in cron.?
# 3  
Old 05-12-2011
Yeah, no errors.

The script runs, it just does not seem to interpret the logic correctly like it does if I run it myself.
# 4  
Old 05-12-2011
try to add the output of ps command in the log file before greping anything from.

Then you can make sure atleast you are getting the program name (as in $PROGRAM1) as required in the ps output.
# 5  
Old 05-12-2011
A "ps" command with no parameters will list the processes for the current terminal only. A "ps" command with no parameters run from cron will fail because there is no current terminal context.

Please post what Operating System and version you are running. There is much variety in the syntax for "ps".
Please post the output from "ps" when run from the command line after starting the application. I'd be surprised to see full path names in that output.

In the end you will need a syntax for "ps" which shows your application when it is running.
# 6  
Old 05-12-2011

I'm running this on a Synology DS210 NAS in the ash shell.

The output for the ps command at the prompt is: -

/volume1 # ps | grep sickbeard
 1561 root      2928 S    grep sickbeard
10514 root      188m S    /var/packages/sab2/target/utils/bin/python /volume1/@appstore/sickbeard/ --quiet
/volume1 #


# 7  
Old 05-12-2011
I have no experience of "ash" or a version of "ps" which behaves like this.

(Appeal for "ash" expert).

General advice is to create a test cron and run the "ps" command and look at the results. Then possibly run the "ps" command with parameters to show processes not started from the current terminal.
If however the "ps" command from a cron is good enough, then replace
grep $PROGRAM1
grep "${PROGRAM1}"

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