There are a few cases in the life of a RaspberryPi owner as it may be useful to display the last bootlog of the RaspberryPi. The bootlog is basically the – much more detailed – journal of your RaspberryPI.
All system-relevant events are entered in the bootlog.
This is handy if you are on the search for a specific problem. Because in the boot log you can then look up, if last (ie before the crash/error) something systemically relevant happened.
How to view the boot log is described in the following article.
I know the following hints are always a bit annoying and seem unnecessary. But unfortunately, many people who knew it "better" from carelessness lost their eyes, fingers or other things or hurt themselves. In comparison, a loss of data is almost not worth mentioning, but even these can be really annoying. Therefore, please take five minutes to read the safety instructions. Even the coolest project is worth no injury or other annoyance. https://www.nerdiy.de/en/sicherheitshinweise/
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To be able to watch the bootlog of your RaspberryPi, it should be ready to access it via SSH.
The following three articles describe what to do to prepare the RaspberryPi so far:
RaspberryPi – Setting up for Nerdiys!
RaspberryPi – The first configuration
RaspberryPi – Controlling the RaspberryPi via SSH
In the following list you will find all the parts you need to implement this article.
Log in via SSH on the RaspberryPi
To get started, you first need to log in to RasPi with SSH on Putty. How to do it is described in the article
Show complete bootlog
Displaying the complete bootlog is possible without much magic with the following command:
“dmesg” is the abbreviation/command for display message. This program outputs the kernel messages on the screen.
Filter bootlog for specific words
Since the command “dmesg” outputs the complete bootlog without further parameters, it can sometimes be tedious to search for a certain keyword in it.
For example, are you looking for a bug with a USB device? So you can filter the output with the following command for lines in which the word “USB” occurs.
dmesg | grep -i usb
The “-i” indicates that the keyword “usb” is case-insensitive. So it will output both lines in which “usb”, “USB” or other combinations of upper and lower case occur.
Have fun with the project
I hope everything worked as described. If not or you have any other questions or suggestions, please let me know in the comments. Also, ideas for new projects are always welcome. 🙂
P.S. Many of these projects - especially the hardware projects - cost a lot of time and money. Of course I do this because I enjoy it, but if you appreciate it that I share these information with you, I would be happy about a small donation to the coffee box. 🙂