Category: Linux

InfluxDB insert multiples values at once using curl

17 August 201717 August 2017 Fabien bash, Orange PI 2 Comments

If you have to insert multiples values in an influxdb database. You can use curl and insert the values one at the time.

But there is a better way like in this example

Let’s say you want to insert your tree loadaverage values in you influxdb database.

First put them into variables using these 3 lines.

onemin=$(cat /proc/loadavg |awk -F' ' '{print $1}')
fivemin=$(cat /proc/loadavg |awk -F' ' '{print $2}')
fifteenmin=$(cat /proc/loadavg |awk -F' ' '{print $3}')

Then using this curl line, insert them all at once in your influxdb database

curl -i -XPOST 'http://localhost:8086/write?db=database' --data-binary "loadavg 1min=$onemin,5min=$fivemin,15min=$fifteenmin"

Orange PI Zero Plus – A simple and, powerfull SBC

16 August 201716 August 2017 Fabien Linux, Orange PI Leave a comment

if you follow what’s new in the SBC world. You must know Xunglong Orange pi, they are a Chinese manufacturer known for making very cheap sbc’s based on Allwinner chip’s.

One of their most interesting sbc’s was the orange pi zero. It was small, powerful, and was ideal for a small headless server. (still available)

It was extremely cheap: less than 10€ but was plagued with some issues like very poor wifi stability, and poor software support from the manufacturer and, only 100mbps on the Ethernet port.

Now Xunlong has come up with an improved version of this board.

The wifi chip is now a well supported Realtek RTL8189FTV
The Ethernet port is now capable of 1Gb/s transfer rate
The cpu is improved with an Allwinner H5
The layout stay exactly the same so case are compatible.

I’ve already ordered one of these boards. At 16,02€ including shipping

It’s available at Aliexpress

OrangePI : Install OpenRTSP on a ARM device

13 August 201713 August 2017 Fabien bash, Linux, Orange PI 1 Comment

One of my project with my OrangePI is to setup the device as a basic IP security camera server ,

the OrangePI zero , will connect to RTSP flux of the IP camera , and dump the stream on to an external disk , where it will be kept for 7 days before getting automaticly deleted
At a latter date i will run a motion detection program on these files and send a mail if motion is detected on a specific part of the frame.

after a little research , i found that a lot of people are using a program called openRTSP to record their RTSP stream to disk

But , after connecting on my OrangePi zero and trying to look for the program i found out that it’s not part of the default installation of armbian stable.

I tried to install the package using apt install openRTSP

apt install openRTSP
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package openRTSP

I went to google and searched , openRTSP package ,and found out , on the debian website that openRTSP is part of the livemedia-utils package,

I went back to my SSH session and typed apt-get install livemedia-utils

root@orangepizero:~# apt-get install livemedia-utils
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
libbasicusageenvironment1 libgroupsock8 liblivemedia50 libusageenvironment3
The following NEW packages will be installed:
libbasicusageenvironment1 libgroupsock8 liblivemedia50 libusageenvironment3 livemedia-utils
0 upgraded, 5 newly installed, 0 to remove and 0 not upgraded.
Need to get 356 kB of archives.
After this operation, 1,187 kB of additional disk space will be used.
Do you want to continue? [Y/n] y

There is no man pages associated with the program , you have to rely on the developer website to understand all the different options . The documentation is available here : http://www.live555.com/openRTSP/ or here if the website is down.
but as usual , in the officials repositories you only get dated version

you might want to compile the source code to have the last version available:

as root

Go to /usr/src: cd /usr/src
Get the live555 liveMedia source code: wget http://www.live555.com/liveMedia/public/live555-latest.tar.gz
Unpack it: tar -xzf live555-latest.tar.gz
Go into the unpacked directory: cd live
Generate the make files: ./genMakefiles linux
Build the code: make
Install the latest version: make install

Bash script to clean movies name

22 June 201722 June 2017 Fabien bash, Linux 3 Comments

The issue when you download movies online, is that most of the time the file name is going to be complete trash , filled with useless info like the team that made the rip or the website from where the movie was downloaded.
This is very annoying when you sort by name and the website made the idiotic decision to put their name in front of the actual film name.

for example here a typical movie name
[ Torrent9.info ] Dont.Think.Twice.2016.FRENCH.WEBRip.XviD-NEWCiNE.avi
the actual useful data that i wish to keep is Dont.Think.Twice.2016.avi

for this purpose i’ve developped a small bash script that will list all the files in a chosen directory then , if necessary , will rename the file.

#!/bin/bash
#the location of the folder full of movies to rename.
for file in /media/freebox/*
do
if [[ -f $file ]]; then
#that line will delete all the text after the date but keep the file extension.
nfile=$(echo $file | sed "s/\(20[0-1][0-8]\).*\(mkv\|avi\|mp4\)/\1.\2/")

#this line is going to try to delete a space a the start of the filename if it exist
nfile=$(echo $nfile | sed  "s/\/ /\//")

#this line is going to delete double dots in the filename and replace them with simple dots
nfile=$(echo $nfile | sed -e "s/\.\./\./g")

#that line is going to delete everything between [] including the [] 
nfile=$(echo $nfile | sed -e 's/\[[^][]*\]//g')


#after all this work on the filename
#you can now check if the any changes have been made , 

if [[ "$file" == "$nfile" ]]
then
   #if no change display this
   echo "Not touched : $file"
else
   #if change detected , rename the file
   echo ______
   echo Renamed :
   echo "Original name : $file"
   echo "Renamed to  : $nfile"
   echo ______
#doing the actual renaming
mv "$file" "$nfile"
fi
fi
done

this is not a very efficient script
but it’s fulfill it’s purpose and very rarely encounter a filename that he is unable to clean.

BASH:check if a number is even or odd

19 June 201719 June 2017 Fabien Linux 5 Comments

In a bash script you might need to check if a var is even or odd ,

in my case im going to use a if to make that check

#!/bin/bash
for i in $(seq 10);do
    if (( $i % 2 )); then
        echo $i is odd
    else
        echo $i is even
    fi
done

You can use this simple code to make that check and display the result.

the result will be :


1 is odd
2 is even
3 is odd
4 is even
5 is odd
6 is even
7 is odd
8 is even
9 is odd
10 is even

BASH : Make a SQL query from bash

14 June 201714 June 2017 Fabien SQL Leave a comment

MySQL is a very convenient way to store data .
To use stored MySQL data in a BASH script you can use this simple command

echo "SELECT * FROM table WHERE column=xyz | MYSQL_PWD=sqlpassword mysql database -u root -s

this will display the result in you terminal without ASCII decorations.
if you need to use that data for something , you can store it in a var

var=$(echo "SELECT * FROM table WHERE column=xyz | MYSQL_PWD=sqlpassword mysql database -u root -s)

BASH : Comparison of values

30 May 201730 May 2017 Fabien Linux Leave a comment

In a if test, you often have to compare the value of two variable
of the value a variable against a fixed value

is equal to
if [ "$a" -eq "$b" ]
if [ "$a" -eq "35" ]

not equal to
if [ "$a" -ne "$b" ]

is greater than
if ["$a" -gt "$b" ]

is greater or equal than
if [ "$a" -ge "$b" ]

is lower than
if [ "$a" -lt "$b" ]

is lower or equal than
if [ "$a" -le "$b" ]

BASH : IP validation

30 May 201730 May 2017 Fabien Linux Leave a comment

if you have a list of ip to validate ,
you can use this little bash script ,
this will open your IP list ,
then test if all the 4 numbers that make a standard IP.are beeten 0 and 255

if the ip is valid then the script will return valid , else it will return : not valid

for IP_ADDRESS in `cat ip-list.txt` ; do
#this var is a test that will see if the number is beetween 1 and 254
test='([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])'
if [[ $IP_ADDRESS =~ ^$test\.$test\.$test\.$test$ ]]; then
echo "valid:     "$IP_ADDRESS
else
echo "not valid: "$IP_ADDRESS
exit
fi
done

after execution , you will get the following result :

valid:     127.0.0.1
valid:     8.8.8.8
valid:     82.48.250.6
valid:     230.230.230.230
not valid: 255.255.2301
valid:     8.8.4.4
not valid: 80.46.70.22.5
valid:     255.255.255.0
valid:     0.0.0.0

Use AWK to display x-th and y-th lines after a regex match

28 May 2017 Fabien Linux Leave a comment

In a script you might be interested to keep 2 or more lines after a regex match ,
the line that interest you are not always going to be right after the match ,
the first one might be X lines after the match and the second one Y lines afters the match

<item desc>
<name=Hammer>
<brand=none>
<weight=700>
<price=12> 
<location=A5H3>
<stock=56>

in this example , i’m interested in keeping the lines with the price and the number in stock
i’m going to use awk to search for item desc , and display the 4th line after the match, and 6th line.

awk '/item desc/{nr[NR+4]; nr[NR+6]}; NR in nr' filename

Bash : Delete some characters from a file with TR

23 May 201728 May 2017 Fabien Linux Leave a comment

in this little example of usage of the command tr
we want to clean a file so the values contained in it can be used
Example File

<10>
<23>
<34>
<78>
<44>
<12>
<40>
<81>
<30>
<11>
<14>
<09>
<02>
<66>

In my example i wish to only keep the value and deleting the character < and >

 cat file| tr -d '<>'

the tr command used with the -d (delete) option will allow you to delete the list of characters contained between the quotes.

You will obtain the following result