Auto-upgrade for Debian based systems
A reliable auto-updater for home use. It can be executed e.g. at boot from /etc/rc.local to keep apt based systems up-to-date. Some output will be logged to /var/log/safe-upgrade.log, in case of upgraded or held packages as well as errors a report will be sent to root@localhost.
Update August, 2020: Command line option "--full" for Dist-Upgrade.
Update June, 2022: sleep-loop for delayed connections (dial-up, WiFi).
#!/bin/sh
#
# safe-upgrade.sh
#
# automated "safe-upgrade" for apt-based distributions with logging
# to /var/log/safe-upgrade.log and a mail to root@localhost in case
# of upgraded packages or problems
# optional command line parameter "--full" will run a dist-upgrade
pingtest=debian.org
hostname=`hostname`
logfile=/var/log/safe-upgrade.log
mailto=root@localhost
if [ X"$@" = X"--full" ] ; then
task=dist-upgrade
else
task=upgrade
fi
sleep 15
echo ----- `date` ----- >> "$logfile"
ping -c 1 "$pingtest" > /dev/null 2>> "$logfile" ||\
{
echo "System upgrade cancelled: No internet connection." |\
tee -a "$logfile" |\
mailx -s "$hostname"\ update\ \*\*\*ERROR\*\*\* "$mailto"
exit 0
}
DEBIAN_FRONTEND=noninteractive
apt-get -q=2 update 2>&1 |\
tee -a "$logfile" |\
mailx -E -s "$hostname"\ update\ \*\*\*ERROR\*\*\* "$mailto"
apt-get "$task" -y -q 2>&1 |\
grep -ve "^(\{0,1\}Reading" \
-e "^Building" \
-e "^Calculating" |\
tee -a "$logfile" |\
grep -ve "^0 upgraded.*0 not upgraded\.$" |\
mailx -E -s "$hostname"\ upgrade\ log "$mailto" &&
echo ----- DONE ----- >> "$logfile"
exit 0
To tame the daily growing log file, add the following lines to /etc/logrotate.conf or into an own file in /etc/logrotate.d/. This will keep compressed archives of the last three months' log files.
### File: /etc/logrotate.conf
/var/log/safe-upgrade.log {
monthly
create
rotate 3
}
If you want the script to be executed by cron, it is necessary to set the $PATH variable - in the script itself, or in the crontab. This example runs every three hours at 45':
### File: root crontab, open to edit with "crontab -e"
# m h dom mon dow command
45 */3 * * * PATH='/usr/sbin:/usr/bin:/sbin:/bin' /path/to/safe-upgrade.sh
Piping dd
Write to several devices at once with dd and tee:
$ dd if=INFILE | tee > (dd of=/dev/sdX) | dd of=/dev/sdY
dd over the network with netcat and bzip compression (not encrypted),
serverside...
$ nc -l 9000 | bzip2 -d | dd bs=1M of=OUTFILE
...and clientside:
$ dd bs=1M if=INFILE | bzip2 -c | nc SERVER 9000
Writing data to an ssh server, using xz transport compression:
$ dd if=INFILE bs= 1M | xz |\
ssh user@host "xz -d | dd of=OUTFILE bs=1M"
Reading data from an ssh server, again with xz transport compression:
$ ssh user@host "dd if=INFILE bs=1M | xz" |\
xz -d | dd of=OUTFILE bs=1M