Cronjob output to log

Question

I'm using a script for testing broadband speed and I would like to set up a cronjob for testing every n minutes and output to a file. The command to launch it from a shell console and append to logfile prepending a line with the current date is

tespeed.py -w | sed -e "s/^/$(date +\"%d-%m-%y\ %T\"), /" >>tespeedlog.csv

But if I use this command in a cronjob something doesn't work; the syslog reports:

Sep 25 13:23:01 raspberrypi /USR/SBIN/CRON[6719]: (pi) CMD (/home/pi/tespeed/tespeed.py -w | sed -e "s/^/$(date +')

What shoud I check?

Answer 1

Create a wrapper script as there may be a problem with escaping date format. The problem seems to be with % character which may be interpreted as a new line specifier in some cron schedulers:

Put this to the file /usr/local/bin/wrpr.sh:

#!/bin/sh
tespeed.py -w | sed -e "s/^/$(date +\"%d-%m-%y\ %T\"), /" >> /tmp/tespeedlog.csv

Make it executable:

chmod u+x /usr/local/bin/wrpr.sh

And schedule it with cron (this will override the current user's crontab):

echo "* * * * * /usr/local/bin/wrpr.sh" | crontab

Otherwise, use crontab -e to add it to the current user's crontab.