How is it drivel. it gives the completed script with an explanation
On Monday, September 21, 2026 at 8:51:02 PM UTC-4 Vince Skahan wrote:
> Please no three page AI drivel. Please.
>
> On Monday, September 21, 2026 at 5:06:31 PM UTC-7 John Bonzey wrote:
>
>> Claude says the following;
>>
>> Subject: Re: bash while loop syntax for weewx backup script
>>
>> Hi,
>>
>> I think I spotted the issue. Your while condition is:
>>
>> while [ systemctl -q is-active weewx ];
>>
>> The problem is that [ ... ] is the "test" command - it doesn't actually
>> run systemctl at all. It just checks whether the string "systemctl -q
>> is-active weewx" is non-empty, which is always true, so the loop never ends
>> based on weewx's real state (it just happens to work when weewx stops
>> quickly, since the loop body still runs and eventually you get lucky with
>> timing).
>>
>> The fix is to drop the [ ] brackets entirely and use the command itself
>> as the condition. In bash, while just checks the exit status of whatever
>> command you give it - it doesn't need [ ] at all unless you're testing a
>> string, number, or file:
>>
>> while systemctl -q is-active weewx;
>> do
>> sleep 1
>> echo $(date): Weewx is still stopping >> /var/log/weewx-backup.log
>> done
>>
>> systemctl -q is-active weewx exits 0 (true) while the service is active,
>> and non-zero once it's fully stopped - which is exactly what you want the
>> loop to check.
>>
>> General rule of thumb: use while [ condition ] for string/number/file
>> tests, and while some_command when you want to "loop while this command
>> succeeds."
>>
>> Your instinct not to copy the DB mid-write is exactly right, and this fix
>> makes that work as intended.
>>
>> One more suggestion: it's worth adding a timeout guard in case weewx ever
>> hangs on stop, so the script can't wait forever. Here's the full script
>> with that added:
>>
>> #!/bin/bash
>> #
>> # Stop weewx service
>> echo $(date): Weewx is stopping >> /var/log/weewx-backup.log
>> systemctl stop weewx
>> #
>> # Check service has stopped (with timeout)
>> timeout=30
>> count=0
>> while systemctl -q is-active weewx;
>> do
>> if [ $count -ge $timeout ]; then
>> echo $(date): Weewx did not stop after ${timeout}s -
>> aborting backup >> /var/log/weewx-backup.log
>> systemctl start weewx
>> exit 1
>> fi
>> sleep 1
>> count=$((count + 1))
>> echo $(date): Weewx is still stopping >> /var/log/weewx-backup.log
>> done
>> echo $(date): Weewx has stopped >> /var/log/weewx-backup.log
>> #
>> # Copy files to backup folder
>> echo $(date): Backup is starting >> /var/log/weewx-backup.log
>> tar -czvf /mnt/backup/weewx-conf.tar.gz /etc/weewx
>> tar -czvf /mnt/backup/weewx-db.tar.gz /var/lib/weewx/weewx.sdb
>> echo $(date): Backup is complete >> /var/log/weewx-backup.log
>> #
>> # Start weewx service
>> systemctl start weewx
>> echo $(date): Weewx is starting >> /var/log/weewx-backup.log
>>
>> With the timeout added, if weewx ever fails to stop within 30 seconds,
>> the script restarts weewx, logs the failure, and exits before touching the
>> backup files - so a hung stop can't leave weewx down or risk copying a
>> database mid-write.
>>
>> Hope that helps!
>> ------------------------------
>> *From:* [email protected] <[email protected]> on behalf
>> of David Schulz <[email protected]>
>> *Sent:* Monday, September 21, 2026 7:22 PM
>> *To:* weewx-user <[email protected]>
>> *Subject:* [weewx-user] Assistance with While condition for backup script
>>
>> Hi
>> I'm attempting to write my first bash script to backup weewx. I'm
>> struggling with the syntax of a condition for a while loop that checks if
>> weewx has stopped or is still stopping.
>>
>> I don't really understand the syntax of the example conditions I can find
>> for various tutorials on using while to create a loop. I cannot find
>> anywhere an exact example of using 'systemctl is-active' as the condition
>> for a while loop.
>>
>> Appreciate any feedback from people more learned than I.
>>
>> TIA
>>
>> Here's what I have at the moment. If I run this script when I know weewx
>> won't be writing to the database, the commands to zip the files into the
>> backup directory all work OK.
>>
>> I don't think I want to be copying the database file in the middle of a
>> write. So I have a separate script with the backup section removed just
>> trying to test the stopping, check has stopped and start parts of the
>> script. I've been unsuccessfully futzing around with different condition
>> syntax and actively trying to run it when weewx is active and the stop
>> command will take a while to execute while the weewx main loop completes.
>> But TBH I'm just wandering about in the dark.
>>
>> ```
>> #!/bin/bash
>> #
>> # Stop weewx service
>> echo $(date): Weewx is stopping >> /var/log/weewx-backup.log
>> systemctl stop weewx
>> #
>> # Check service has stopped
>> while [ systemctl -q is-active weewx ];
>> do
>> sleep 1
>> echo $(date): Weewx is still stopping >> /var/log/weewx-backup.log
>> done
>> echo $(date): Weewx has stopped >> /var/log/weewx-backup.log
>> #
>> # Copy files to backup folder
>> echo $(date): Backup is starting >> /var/log/weewx-backup.log
>> tar -czvf /mnt/backup/weewx-conf.tar.gz /etc/weewx
>> tar -czvf /mnt/backup/weewx-db.tar.gz /var/lib/weewx/weewx.sdb
>> echo $(date): Backup is complete >> /var/log/weewx-backup.log
>> #
>> # Start weewx service
>> systemctl start weewx
>> echo $(date): Weewx is starting >> /var/log/weewx-backup.log
>> ```
>>
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>>
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