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My goal was to make my Pi create its own WiFi on start so that I can connect to it wirelessly.

I have succeeded by creating a crontab entry (using sudo crontab -e):

@reboot /path/to/create_ap.sh &

where create_ap.sh is a script launching create_ap:

#!/bin/bash
sudo create_ap -n wlan0 MySSID MyPass --daemon

However, I've failed to do this without an additional script: both

@reboot create_ap -n wlan0 MySSID MyPass --daemon

and

@reboot create_ap -n wlan0 MySSID MyPass --daemon &

didn't work as expected (I've also tried to add full path, /usr/bin/create_ap like suggested in comments but that didn't help).

So does crontab allow parameters after the command? (I suspect that only @reboot create_ap bit works in practice, but failed to google that) Or is there some other problem with these lines in crontab and I can adjust them so that an external script is not needed?

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  • Does using the full path to create_ap in your crontab work? (I believe the path is /usr/bin/create_ap). Does your crontab change the PATH variable in any other way? – Aurora0001 Jan 1 '18 at 10:56
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    @Aurora0001 thanks, which create_ap says /usb/bin/create_ap and I've tried full path in crontab but that didn't help – YakovL Jan 1 '18 at 17:51
  • Is this a user crontab, or your system crontab? If it's a user crontab (created with crontab -e) one difference is that the command kicks off as your user, whereas your script includes sudo to execute the command as root. This should go into a system crontab to execute as root on startup. – bobstro Jan 2 '18 at 14:38
  • @bobstro I only used sudo crontab -e so that's root crontab, I guess. Will add this to the question – YakovL Jan 2 '18 at 18:44
  • You've specified a path to the script in your working example, but not a path the the create_ap script in the non-working entries. Try prepending a path to create_ap. Check logs or email for errors. – bobstro Jan 2 '18 at 20:06
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Well, the .sh script calls sudo before create_ap. Either run the crontab entry as root, or prepend the sudo. So try @reboot sudo /usr/bin/create_ap -n wlan0 MySSID MyPass --daemon

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  • I used sudo crontab -e which means I used the first option, right? I've read also that the second option is not a proper approach: askubuntu.com/a/173930/532531 (but actually I've already tried the line you proposed as well) – YakovL Jan 2 '18 at 18:48
  • Yes, sudo crontab -e works if you want to run the crontab entry as root directly. Considering the second option, you can mitigate that risk from the link by putting pi ALL= NOPASSWD: /usr/bin/create_ap in /etc/sudoers.d/pi. – steviethecat Jan 3 '18 at 7:41
  • Reading github.com/oblique/create_ap also gives the alternative to start it from systemd (also check github.com/oblique/create_ap/issues/4). – steviethecat Jan 3 '18 at 7:44

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