community – ping from script launched by cron

The particular motive for the failure is that the setting in cron is a special setting than “… in standard interactive shell”. If you wish to study how the setting is completely different in cron vs your interactive shell, attempt working printenv (or env) from every & observe the variations; i.e.:

% crontab -e
...  crontab opens within the editor you've got chosen as default (an setting variable!!) 
...  add following line to your crontab: 

* * * * *  /usr/bin/printenv > $HOME/mycronenv.txt 2>&1

... save & exit the editor

Now, out of your interactive shell, enter the next command:

% /usr/bin/printenv > $HOME/myshellenv.txt 2>&1 

Subsequent, examine the environments listed within the two information:

cat $HOME/myshellenv.txt
...
cat $HOME/mycronenv.txt
...

See the distinction? Word particularly the distinction within the PATH setting variable.

Subsequent, discover out the place your ping command is situated:

whereis ping
ping: /sbin/ping /usr/share/man/man8/ping.8

Ask your self, “Is /sbin included within the PATH setting variable for cron?”

The reply is: “No”

What ought to I do about that?

Most likely the best factor to do is change a line in your script:

FROM: 
ping localhost 

TO:
/sbin/ping -c 1 localhost

Please notice the addition of -c 1 has nothing to do with setting, that’s merely to maintain you from clogging your system with a bunch of ping processes!!

One different factor you could must do beneath macOS:

1. Open System Settings, then choose Privateness and Safety, after which Full Disk Entry

2. Verify to confirm that cron is listed (and enabled) for “Full Disk Entry”

3. IF IT IS LISTED, BUT NOT ENABLED: Click on the toggle to allow it

4. IF IT IS NOT LISTED: Click on the + on the backside of the itemizing

5. Add cron (beneath /usr/sbin/cron to offer cron “Full Disk Entry”)

And FWIW, see this recipe overlaying utilization of cron & crontab