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This question is related to Debian 8.4.

I applied the same updating mechanism to several desktop stations and one unused server. This problem appeared on the server, but I suspect it will happen on all those stations too.

As solved in this thread, I managed to get the cron job logged, now I waited for an update. Here it comes and so a piece of error information, which is total gibberish to me right now.

Please first see how I set it up here: How do I know if crontab is working fine?

The relevant part of the log starts when it wants to download archives.

Apr  8 00:00:42 vb-srv-debian updates: Need to get 108 MB of archives.
Apr  8 00:00:42 vb-srv-debian updates: After this operation, 20.5 kB of additional disk space will be used.
Apr  8 00:00:42 vb-srv-debian updates: Get:1 http://dl.google.com/linux/chrome/deb/ stable/main google-chrome-stable amd64 49.0.2623.112-1 [48.5 MB]
Apr  8 00:00:42 vb-srv-debian updates: Get:2 http://nightly.odoo.com/9.0/nightly/deb/ ./ odoo 9.0c.20160407 [59.6 MB]
Apr  8 00:00:54 vb-srv-debian updates: Reading changelogs...
Apr  8 00:01:01 vb-srv-debian updates: debconf: unable to initialize frontend: Dialog
Apr  8 00:01:01 vb-srv-debian updates: debconf: (TERM is not set, so the dialog frontend is not usable.)
Apr  8 00:01:01 vb-srv-debian updates: debconf: falling back to frontend: Readline
Apr  8 00:01:01 vb-srv-debian updates: debconf: unable to initialize frontend: Readline
Apr  8 00:01:01 vb-srv-debian updates: debconf: (This frontend requires a controlling tty.)
Apr  8 00:01:01 vb-srv-debian updates: debconf: falling back to frontend: Teletype
Apr  8 00:01:01 vb-srv-debian updates: dpkg-preconfigure: unable to re-open stdin:
Apr  8 00:01:01 vb-srv-debian updates: Fetched 108 MB in 11s (9,111 kB/s)
Apr  8 00:01:01 vb-srv-debian updates: dpkg: warning: 'ldconfig' not found in PATH or not executable
Apr  8 00:01:01 vb-srv-debian updates: dpkg: warning: 'start-stop-daemon' not found in PATH or not executable
Apr  8 00:01:01 vb-srv-debian updates: dpkg: error: 2 expected programs not found in PATH or not executable
Apr  8 00:01:01 vb-srv-debian updates: Note: root's PATH should usually contain /usr/local/sbin, /usr/sbin and /sbin
Apr  8 00:01:01 vb-srv-debian updates: E: Sub-process /usr/bin/dpkg returned an error code (2)

I suspect the main, if not only one problem is related to $PATH variable, which I currently don't understand, how it is used.

While being root, the following variable values are returned:

$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

$ echo $TERM
xterm
Vlastimil Burián
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1 Answers1

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cron typically runs things in a fairly minimal environment (man 5 crontab to see what exactly), which probably doesn't have enough in its path for this. If you want to see what is in the path, you can always run printenv > /tmp/cron_env from (presumably at a time in the near future) to see. Generally, you can just define an updated PATH in your crontab file; again see man 5 crontab for details.

Vlastimil Burián
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arcticmac
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