Score:0

What's this command - 0 */12 * * * root test -x /usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep int(rand(43200))' && certbot -q renew?

cn flag
0 */12 * * * root test -x /usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep int(rand(43200))' && certbot -q renew

I understand the meaning of 0 */12 * * *

Following that is root which seems to be the username. What is the meaning of the test -x.... onwards?

Score:2
ec flag
EML

This is a crontab entry. root specifies that the job must be run as user root (so, it's slightly more complex than the standard user crontab entry). The rest of the line is the job to run. The job is run every 12 hours.

The job is

test -x /usr/bin/certbot -a \! -d /run/systemd/system && perl -e 'sleep int(rand(43200))' && certbot -q renew

Basically, this checks whether Certbot is installed, waits a random time of up to 12 hours to avoid congestion, and then runs certbot -q renew to renew a certificate if necessary.

Cerbot auto-renewal setup is described here.

mangohost

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