Top Command Output is Empty when run from cron

Question

I was trying to redirect the TOP command output in the particular file in every 5 minutes with the below command.

top -b -n 1 > /var/tmp/TOP_USAGE.csv.$(date          


        

Answer 1

I met the same problem as you.

Top command with -b option must be added.Saving top output to variable before we use it.

the scripts are below

date >> /tmp/mysql-mem-moniter.log

MEM=/usr/bin/top -b -n 1 -u mysql

echo "$MEM" | grep mysql >> /tmp/mysql-mem-moniter.log

Answer 2

Most likely the environment passed to your script from cron is too minimal. In particular, PATH may not be what you think it is (no profiles are read by scripts started from cron).

Place PATH=$(/usr/bin/getconf PATH) at the start of your script, then run it with

/usr/bin/env -i /path/to/script

Once that works without error, it's ready for cron.