Ubuntu

How to fix empty system log (“syslog”) on Linux

Posted on by mikaelleven

If your system log (“syslog”) file is empty something is probably wrong. Under normal conditions the system writes to this log all the time and you can easily verify this by executing the following command.

$ cat /var/log/syslog

If everything is working as expected a lot of log messages should be printed on screen. If the syslog however is empty this might be caused by faulty file permissions (wrong owner). You can also try to post a test message to the log yourself to ensure nothing actually gets written to the log.

$ logger This is a test message
$ cat /var/log/syslog
Nov 13 19:58:12 MyComputer root: This is a test message

The result should now look something like the above if the syslog is actually working. If the file however is still empty then you need to verify the file permissions using the ls command:

$ ls -l /var/log/syslog
 -rw-r--r-- 1 root adm 21874 Nov 13 19:35 /var/log/syslog

Here you want to make sure the owner is syslog and the group is adm. If the owner is something other than syslog (as in this example where the owner is root) you could easily solve this by simply change the owner of the file so the “syslog” user can write to the syslog-file:

$ chown syslog:adm /var/log/syslog

Now you can once again run the ls command to make sure file permissions (ownership) is as expected:

$ ls -l /var/log/syslog
-rw-r--r-- 1 syslog adm 21874 Nov 13 19:35 /var/log/syslog

 

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Your First Raspberry Pi: A Buyer’s Guide

Posted on by mikaelleven

Pi_2_Model_BI found this great post about the choices you need to make when buying your first Raspberry Pi. Although being a great guide when deciding about which model to choose and what complementary hardware you need, it is a bit outdated. I would recommend you read the guide, however with following additions:

Model A vs A+

This is the differences with A+ compared to the initial Model A:

  • More GPIO. The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model A and B.
  • Micro SD. The old friction-fit SD card socket has been replaced with a much nicer push-push micro SD version.
  • Lower power consumption. By replacing linear regulators with switching ones we’ve reduced power consumption by between 0.5W and 1W.
  • Better audio. The audio circuit incorporates a dedicated low-noise power supply.
  • Smaller, neater form factor. We’ve aligned the USB connector with the board edge, moved composite video onto the 3.5mm jack, and added four squarely-placed mounting holes. Model A+ is approximately 2cm shorter than the Model A.

Recommended for embedded projects and projects which require very low power, and which do not require Ethernet or multiple USB ports.

Mode B vs B+

Model B+ should not be mixed up with the Model B Rev 2 (which is simply a slightly updated Model B rev 1with minor differences). However, the differences between Model B and B+ is on the other significant.

  • More GPIO. The GPIO header has grown to 40 pins, while retaining the same pinout for the first 26 pins as the Model A and B.
  • More USB. We now have 4 USB 2.0 ports, compared to 2 on the Model B, and better hotplug and overcurrent behaviour.
  • Micro SD. The old friction-fit SD card socket has been replaced with a much nicer push-push micro SD version.
  • Lower power consumption. By replacing linear regulators with switching ones we’ve reduced power consumption by between 0.5W and 1W.
  • Better audio. The audio circuit incorporates a dedicated low-noise power supply.
  • Neater form factor. We’ve aligned the USB connectors with the board edge, moved composite video onto the 3.5mm jack, and added four squarely-placed mounting holes.

The Model B+ is perfectly suitable for use in schools: it offers more flexibility for learners than the leaner Model A or A+, which are more useful for embedded projects and projects which require very low power, and has more USB ports than the Model B.

The New Raspberry Pi 2

The Raspberry Pi 2 is the next generation of Model B/B+, and it is not even mentioned in the original post. It basically is a beefed up Model B+ with better CPU and more RAM, making it even more suitable for HTPC, NAS and similar usages.

Because it has an (quad-core) ARMv7 processor, it can run the full range of ARM GNU/Linux distributions, including Snappy Ubuntu Core, as well as Microsoft Windows 10. And due to being more powerful the “Pi 2” will be slightly more power-hungry compared to the Model B+ (up to about 0.5-1w more), and especially compared to the Model A+.

Original post

http://computers.tutsplus.com/tutorials/your-first-raspberry-pi-a-buyers-guide–mac-54134