Was building a RPi3 machine and got the following error after an update.
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iptables v1.4.21: can't initialize iptables table `nat': Table does not exist (do you need to insmod?) |
Turns out nothing to worry about, just reboot the Pi.
The new Raspberry Pi 3 A+ was just released, basically its a cut down version of the 3 B+.
Here is a comparison between the two.
| RPi3A+ | RPi3B+ | Difference | |
| CPU | BCM2837B0 1.4GHz | BCM2837B0 1.4GHz | Same |
| Memory | 512MB | 1GB | -512MB |
| Network | Wifi, Bluetooth | Ethernet, Wifi, Bluetooth | -Ethernet |
| Size | 65mm x 56mm | 85mm X 56mm | -20mm Shorter |
| USB Ports | 4 | 1 | -3 |
I wanted a script which would read all the live dump1090 aircraft data and log it to a mysql database.
This base script does it, it will dump all the data to Mysql every minute.
It will start the dump1090 server and kick off a process which reads/sorts and inserts.
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#!/bin/bash dbserver="localhost" dbuser="flighttrax" dbpw="flighttrax" dbtable="flighttrax" clientid="1000000" core="/root/file.txt" dump="/tmp/dump.txt" selectdate=`date -d "1 min ago" '+%Y/%m/%d,%H:%M'` listener="localhost" listenerport="30003" ncpid=`ps waux | grep "nc $listener $listenerport"| grep -v grep | awk '{print $2}'` dumppid=`ps waux | grep "dump1090"| grep -v grep | awk '{print $2}'` log="/var/log/flighttrax.log" echo "`date`" >> $log echo "`date` - Starting script" >> $log echo "`date` - Netcat pid is $ncpid" >> $log echo "`date` - Dump1090 pid is $dumppid" >> $log if [ -z $dumppid ] then echo "`date` - Dump1090 not started yet" >> $log /root/dump1090/dump1090 --net --quiet & echo "`date` - Started Dump1090" >> $log exit fi if [ -z $ncpid ] then echo "`date` - Netcat not started yet" >> $log nc $listener $listenerport >> $core echo "`date` - Started NC" >> $log exit fi echo "`date` - Copying last minute" >> $log cat $core | grep $selectdate > $dump echo "`date` - Calculating Entries" >> $log entries=`wc -l $dump` echo "`date` - Total of $entries to import" >> $log echo "`date` - Starting FOR statement" >> $log for i in `cat $dump | awk -F ',' '{print $5}' | sort | uniq | sed '/^$/d'` do reg=$i flightnum=`cat $dump | grep $i | awk -F ',' '{print $11}'| sort| uniq | sed '/^$/d'|awk '{print $1}'|sed 's/\r//'` for i in `cat $dump | grep $reg | awk -F ',' '{print $7","$8","$15","$16","$12}'| sort| uniq | sed '/,,/d'` do date=`echo $i| awk -F ',' '{print $1}' | sed 's#/#-#g'` time=`echo $i| awk -F ',' '{print $2}'` lat=`echo $i| awk -F ',' '{print $3}'` long=`echo $i| awk -F ',' '{print $4}'` alt=`echo $i| awk -F ',' '{print $5}'` echo "$reg,$flightnum,$date,$time,$lat,$long,$alt" mysql -uflighttrax -pflighttrax flighttrax -e "INSERT INTO flighttrax VALUES ('','$clientid','$reg','$flightnum','$date $time','$lat','$long','$alt');" done done echo "`date` - For completed" >> $log echo "`date` - Deleting temp files" >> $log rm $dump echo "`date` - Done." >> $log |
Quite often you need to write scripts which need to email you urgent information, there is a very simply way to do this.
First we need to install an email server to transmit the emails.
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sudo apt-get install postfix |
Then insert the following into your script.
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mail -s "Host File" name@address.com < /etc/hosts |
In the above example it will email a copy of your local host file, change be change for any file you want transmitted.
See this script for a working example.
My new internet connection with NBN changes the IP on a regular basis, but I wanted visibility as to how often.
So I’ve written a bash script which records your IP and date, once it changes it records your new IP and sends you an email to notify you of the new change.
This is completed by querying your no-ip dns record.
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#!/bin/bash domain="$1" log="ip_log_$domain.txt" email="name@gmail.com" currentip=$(nslookup ${domain} | grep Address | tail -n 1| awk '{print $2}') lastip=$(cat $log | tail -n 1 | awk -F ',' '{print $2}') if [ -z ${lastip} ] then echo "$(date),${currentip}" >> ${log} exit 0 fi if [ ${lastip} == ${currentip} ] then echo "Nothing changed." else echo "$(date),${currentip}" >> ${log} mail -s "IP Address Change" ${email} < /home/tdionisakos/ip_log_${domain}.txt fi |
Usage
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./ip_checker.sh domain.no-ip.com |
Cron Entry. (runs every hour)
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33 * * * * /home/tdionisakos/ip_change.sh hop.no-ip.com |
I was running Nextcloud on a Raspberry Pi zero w, the performance is not there.
I ran top to determine the IO Wait times, it was high. High enough that the performance would be impacted.
I ran a test on two different cards.
The is a Sandisk Ultra 16gb ($9) and the Sandisk Extreme Pro 128gb ($120), looks like the price does not improve performance on the raspberry pi Zero. I will write another article when I test the latest Raspberry Pi and see if the results change.
Sandisk Ultra
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root@zero:~# dd bs=1M count=1000 if=/dev/zero of=test.iso 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB, 1000 MiB) copied, 48.7425 s, 21.5 MB/s |
Sandisk Extreme Pro
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pi@raspberrypi:~ $ dd bs=1M count=1000 if=/dev/zero of=test.iso 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB, 1000 MiB) copied, 51.0118 s, 20.6 MB/s pi@raspberrypi:~ $ |
Im currently running a Linux desktop, the other day the disk become corrupt and I lost my home area. Not a big problem as I dont store much data, but I lost all my ssh keys, configs etc. It took a few days to recover.
In an effort to stop that from happening again I want to backup all my data to the company file server, but I dont want them to have access to my keys and configs ect.
So I have scripted a backup which will encrypt on the fly. Through it into cron and you have a daily backup.
This is the command you run to create backup, notice the password is in the command. This is allow for automated backups using Cron.
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tar -czf - /home/username/* | openssl enc -e -aes256 -pass pass:password -out /mnt/backupmount/backup.tar.gz |
And the following command is to run a restore, once executed you will be prompted for the password.
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openssl enc -d -aes256 -in /mnt/backupmount/backup.tar.gz | tar xz |
I had problems mounting NFS shares in my docker container, error would appear with permissions denied. This is the fix which worked for me.
Inside the container execute the following.
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apt-get update apt-get install nfs-common -y |
on the host execute the following to mount the share.
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docker exec --privileged=true 191b603b04b9 mount -t nfs -o nolock 192.168.1.5:local /mnt |
This has to be one of the easiest tasks!
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apt-get update apt-get upgrade -y curl -sSL https://get.docker.com | sh |
This will completed all the tasks in the background
Enjoy
The new Raspberry Pi 3 B+ has been release. Its the first release in a while.
I just wanted to highlight the major differences between the 3B and 3B+ models.
| 3 B | 3 B+ | |
| CPU | 1.2 GHz | 1.4 GHz |
| Wired | 10/100BASE-T | 10/100/1000BASE-T |
| Wireless | 802.11ac (2.4ghz) | 802.11n (2.4ghz and 5ghz) |
| Bluetooth | 4.1 | 4.2 |
