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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Linux’ Category

Hosting Grumpydev Imageflair locally

Posted by jpluimers on 2017/04/06

Even though StackOverflow and StackExchange now have implemented their own ImageFlair, I still like the original imageFlair that Grumpydev made at Stack Overflow – Share Your Flair – Now in PNG! | GrumpyDev

Grumpydev Imageflair

Stackoverflow imageflair

Stackoverflow imageflair

Alas, the Grumpydev site doesn’t properly support https and Grumpydev cannot change it because of shared hosting limitations, so I wanted to host ImageFlair locally and even see if I could make it StackExchange aware:

Stackexchange flair

Stackexchange flair

Well, I need to do that propertly another time as the first thing I bumped into was this:

PHP Fatal error: Call to undefined function imagecreatefrompng() in /srv/www/vhosts/pluimers.com-ssl/stackoverflow/imageFlair/imageFlair.php on line 42

For now I’ve fixed the first by installing php5-gd (although an SO answer suggests php-gd, openSuSE uses the php-version number for installing modules).

zypper install php5-gd
php -m
rcapache2 stop
rcapache2 start
rcapache2 status

This will install the module, check with php if it is indeed installed, then restart apache to let it use the updated module.

After that, I bumped into a second thing: the image is blank.

Blank imageFlair

Blank imageFlair

I also bumped into a third thing: the .htaccess file rewrite doesn’t work:

https://www.pluimers.com/stackoverflow/imageFlair/so/1.png gave me a 404 error whereas https://www.pluimers.com/stackoverflow/imageFlair/imageFlair.php?userid=1&mode=so “works” (i.e. generates a blank image).

That one was sort of easy to solve.

First of all, apparently I didn’t have all the required apache modules installed. The not-so-easy part is that apache uses two different aliases for modules: the ones listed by apache2ctl -M 2>&1 | sort are in a different format than the ones you mention in .htaccess and .conf files. Oh and of course the -M (nor the -t -D DUMP_MODULES) aren’t listed ore hinted in the apachectl documentation: that would be too easy. They are listed in the httpd2 documentation.

The .htaccess file needs mod_rewrite and mod_expires, but apache2ctl names them rewrite_module and expires_module.

Enabling these was easy, but you have to remember that a2enmod strips the prefix/suffix of the module name (I already had expires_module (shared) installed so this only shows how to enable mod_rewrite):

a2enmod rewrite
rcapache2 stop
rcapache2 start
rcapache2 status

NB: mod_rewrite wasn’t enable by default and before enabling it, read about the risks of mod_rewrite.

Then it still didn’t work, and then it occurred to me that likely I didn’t even have Apache2 allow for using .htaccess as the regexes in the .htaccess were fine. And indeed: .htaccess wasn’t enabled according to the steps at Making sure .htaccess and mod_rewrite are working as they should | Bolt Documentation. And indeed, the Apache documentation indicates when (not) to use .htaccess.

By setting the AllowOverride to both FileInfo as specified by RewriteRule and Indexes as specified by ExpiresActive (trying to refrain from AllowOverride All) for only this specific directory, I think I struck the right balance:


<Directory "/srv/www/vhosts/pluimers.com-ssl/stackoverflow/imageFlair">
# for .htaccess in that directory
AllowOverride FileInfo Indexes
</Directory>

And the final thing is that the logic around StackExchange flair is a tad more complex than I hoped for. And on that bombshell…

–jeroen

Posted in *nix, Apache2, Development, Linux, openSuSE, PHP, Power User, Scripting, Software Development, SuSE Linux | 1 Comment »

OpenSuSE Tumbleweed on Raspberry Pi: getting `vcgencmd version` to work to see which GPU firmware you have

Posted by jpluimers on 2017/04/05

When you search for raspberry pi firmware version check

Installing and running rpi-update will – besides updating the GPU firmware – also install vcgencmd, I got this result:

statler:~ # LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/vc/lib/
statler:~ # export LD_LIBRARY_PATH
statler:~ # /opt/vc/bin/vcgencmd version
Jul 15 2016 17:50:10 
Copyright (c) 2012 Broadcom
version efa728fef77ea14ceb1500caf0146395fa282a0f (clean) (release)

But I wanted to be able to run vcgencmd before installing updates.

openmamba indicates it’s part of their raspberrypi-utils package with sources in the raspberrypi-userland package tracing back to git://github.com/raspberrypi/userland.git which is at https://github.com/raspberrypi/userland.

So I had two choices: compile https://github.com/raspberrypi/userland or find the binaries that rpi-update installs and are already runnable. I went for the second first by digging in https://github.com/Hexxeh/rpi-update/blob/master/rpi-update which on one of the first lines points to https://github.com/Hexxeh/rpi-firmware where the binaries are stored under https://github.com/Hexxeh/rpi-firmware/tree/master/vc/softfp/opt/vc.

The logic for copying the files is in the update_vc_libs function. The calling do_update function updates a lot more, including the firmware. So I wrote a quick pull request to just download the userland binaries:

Feature SKIP_FIRMWARE for #220: forces SKIP_KERNEL=1 and also skip the kernel.img files and the kernel modules: This effectively only installs the userland and SDK.

Source: #220 feature `SKIP_FIRMWARE` by jpluimers · Pull Request #221 · Hexxeh/rpi-update

Hopefully it gets merged in. When not, then you can always take a look at the commit: #220 feature SKIP_FIRMWARE · jpluimers/rpi-update@5a2ec0b

Run these commands to get going:

cd /root/bin
wget https://raw.githubusercontent.com/jpluimers/rpi-update/5a2ec0bc552436d58127cc20e3791cb5b90fd5ba/rpi-update
chmod +x rpi-update
SKIP_FIRMWARE=1 UPDATE_SELF=0 ./rpi-update

You should see this when updating:

 *** Raspberry Pi firmware updater by Hexxeh, enhanced by AndrewS and Dom
 *** We're running for the first time
 *** Backing up files (this will take a few minutes)
 *** Remove old firmware backup
 *** As requested, not updating firmware and kernel modules
This update bumps to rpi-4.4.y linux tree
Be aware there could be compatibility issues with some drivers
Discussion here:
https://www.raspberrypi.org/forums/viewtopic.php?f=29&t=144087
##############################################################
 *** Downloading specific firmware revision (this will take a few minutes)
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   168    0   168    0     0    361      0 --:--:-- --:--:-- --:--:--   362
100 51.2M  100 51.2M    0     0  1246k      0  0:00:42  0:00:42 --:--:-- 1446k
 *** As requested, not updating firmware and kernel
 *** As requested, not updating firmware and kernel modules
 *** Updating VideoCore libraries
 *** Using HardFP libraries
 *** Updating SDK
 *** Running ldconfig
 *** Storing current firmware revision
 *** Deleting downloaded files
 *** Syncing changes to disk
 *** If no errors appeared, your firmware was successfully updated to 818a860cf690d64c62d3227ad9c36d5867a671c2
 *** A reboot is needed to activate the new firmware

And the final goal of checking the firmware version now works:

# LD_LIBRARY_PATH=/opt/vc/lib /opt/vc/bin/vcgencmd version
Jul 15 2016 17:50:10 
Copyright (c) 2012 Broadcom
version efa728fef77ea14ceb1500caf0146395fa282a0f (clean) (release)

–jeroen

Posted in Development, Hardware Development, Linux, openSuSE, Raspberry Pi, SuSE Linux, Tumbleweed | Leave a Comment »

Powering Raspberry Pi devices from a Fritz!Box USB connection

Posted by jpluimers on 2017/03/30

I tried to power both Raspberry B+ and Raspberry 2 B devices via the USB ports of both a Fritz!Box 7490 and Fritz!Box 7360.

At first this works, but the Raspberry B+ devices over time would become unstable: not being able to ping and/or boot.

So below are some links on power requirements and powering Raspberry Pi A, B, A+, B+, 2B and zero.

Fazit/TL;DR: use an external power supply when available.

Read the rest of this entry »

Posted in *nix, Development, Fritz!, Fritz!Box, Hardware Development, Internet, Linux, openSuSE, Power User, Raspberry Pi, SuSE Linux | Leave a Comment »

`-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)` on fresh Raspbian on Raspberry

Posted by jpluimers on 2017/03/24

Every time I logged onto a freshly installed Rasbian system (Debian Jessie), I had this message:

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sat Aug 27 19:52:33 2016 from 192.168.171.24
-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

Asking for the locale settings would give this:

jeroenp@raspberrypi:~ $ locale
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_MESSAGES to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_GB.UTF-8
LANGUAGE=
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=en_US.UTF-8

Searching for raspbian jessie “-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)” I found fix locale issue #15 · scaleway/image-debian@543e9b4 [WayBack] that fixes Locale issue on Debian Jessie · Issue #15 · scaleway/image-debian · GitHub [WayBack]:

When logging into to a freshly booted debian jessie image:

-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)
-bash: warning: setlocale: LC_ALL: cannot change locale (en_US.UTF-8)

Source: Locale issue on Debian Jessie · Issue #15 · scaleway/image-debian

I changed the crux of that solution to this one:

echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen && locale-gen

When running, it showed this:

# echo "en_US.UTF-8 UTF-8" >> /etc/locale.gen && locale-gen
Generating locales (this might take a while)...
  en_GB.UTF-8... done
  en_US.UTF-8... done
Generation complete.

And logging this:

The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Sat Aug 27 20:26:34 2016 from 192.168.171.24

Problem solved: 1 line of code!

–jeroen

Posted in *nix, Arduino, Debian, Development, Hardware Development, Linux, Power User, Raspberry Pi, Raspbian | 1 Comment »

Kylix: The Real Lowdown – I wrote this in 2000 too

Posted by jpluimers on 2017/03/23

A while ago – while researching yesterdays post – I came across the below article that I wrote back in august 2000 for The Delphi (by Pinnacle Publishing – long gone by now) and on-line at http://www.delphidevelopernewsletter.com/dd/DDMag.nsf/WebIndexByIssue/B8FC16D8103A3760852568F600559A83

I found a cached copy first at http://www.txsz.net/xs/delphi/2/%E6%8A%80%E5%B7%A7%E5%8F%8A%E7%BB%8F%E9%AA%8C/KYLIX%EF%BC%9A%20%E7%9C%9F%E7%9B%B8.HTM and back-tracked from there.

Since the wayback machine isn’t indexed, I salvaged the copy below.

On the Delphi Tokyo release yesterday [WayBackTokyo is available today! – Martin Sedgewick – Google+: I will only try that after Update 1 is released, but based on the [WayBackWhat’s New – RAD Studio:

Like

  • Reintroduction of Linux support. Finally.
  • 64-bit as target: server side, the 32-bit days have been over for a long time
  • one-based strings (boy, I’m glad they didn’t continue on the zero-based strings they did on mobile)

Dislike

  • No openSUSE support where SuSE was the primary partner during Kylix development and launch, just search SuSE kylix; heck the registration guide is still up at [WayBackSDB:Kylix – openSUSE
  • LLVM compiler as it is way too slow for my development cycles
  • ARC based

Time will tell if it works better for me than the .NET Core for Linux I’ve been using until now.

–jeroen
Read the rest of this entry »

Posted in *nix, Delphi, Development, History, Kylix, Linux, openSuSE, Power User, Software Development, SuSE Linux | 4 Comments »

ducks: How Do I Find The Largest Top 10 Files and Directories On a Linux / UNIX / BSD?

Posted by jpluimers on 2017/03/20

Explains how to find out top 10 files and directories under Unix / Linux using sort and du command in human-readable format.

Interesting, especially

alias 'ducks=du -cks * | sort -rn | head'

Source: How Do I Find The Largest Top 10 Files and Directories On a Linux / UNIX / BSD?

via: Joe C. Hecht and nixCraft.

–jeroen

Posted in *nix, *nix-tools, Apple, BSD, Linux, Mac, Mac OS X / OS X / MacOS, Power User | Leave a Comment »

node.js – a nightmare to get started. Did I try the wrong technology for my problem?

Posted by jpluimers on 2017/03/08

Most of my web-stuff is on Apache. Which works fine, has TLS/SSL enabled, etc.

But I wanted to do server-side JavaScript. Which somehow is a forrest without trees, or a nightmare to get started, especially on OpenSuSE.

First of all, virtually all examples explain how to run node as a script. But none explain where to save it, how to run it as a service (and restart when it crashes: it will crash) or how to run multiple sites under it. And the scripts seems to listen to a TCP port by themselves so they operate as a full server by themselves. Nice for a fully fledged portal, but not for some one-offs.

Some links below hopefully will get me re-started later on, but for now, I’ve given up: the out-of-the-box experience is totally non-intuitive.

Maybe what I really want is something else: I want JavaScript stuff that normally renders a page in the browser through the dom to run server side so I can run XMLHttpRequest to various places without bumping into CORS stuff but still render a page DOM.

If you know a better way to do what I want (serving small mostly single-page scripts written in an easy to debug/trace language) let me know.

So basically work around this:

XMLHttpRequest cannot load http://myApiUrl/login. No
'Access-Control-Allow-Origin' header is present on the requested
resource. Origin 'null' is therefore not allowed access.

Read the rest of this entry »

Posted in *nix, Apache2, Development, JavaScript/ECMAScript, Linux, openSuSE, Power User, Scripting, Software Development, SuSE Linux | 1 Comment »

The woods and trees of OpenSuSE on single-board computers – image abbreviations – and getting it installed using OS X

Posted by jpluimers on 2017/02/27

Finding the right image

There are many single-board computers on the OpenSuSE hardware-compatibility list (HCL), including:

A lot of them have ready to go images, often for Tumbleweed, however none of the pages explain the below image differences hence the one-line for each:

Since I wanted a headless system, JeOS was what I needed.

As it wasn’t available for my ODroid C1+ but was for my Raspberry Pi 2 and as my main machine is a 15″ Retina MacBook Pro Late 2013 [WayBack] below are the steps I used to get the image working.

Installing the Raspberry Pi 2 image using OS X

The below Raspberry Pi2 link will redirect to the correct image in the generic download directory http://download.opensuse.org/repositories/devel:/ARM:/Factory:/Contrib:/RaspberryPi2/images/

http://download.opensuse.org/repositories/devel:/ARM:/Factory:/Contrib:/RaspberryPi2/images/openSUSE-Tumbleweed-ARM-JeOS-raspberrypi2.armv7l.raw.xz

For other Raspberry Pi versions, you can find them here:

http://download.opensuse.org/repositories/devel:/ARM:/Factory:/Contrib:/RaspberryPi3/images/openSUSE-Tumbleweed-ARM-JeOS-raspberrypi3.aarch64.raw.xz

http://download.opensuse.org/ports/armv6hl/tumbleweed/images/openSUSE-Tumbleweed-ARM-JeOS-raspberrypi.armv6l-Current.raw.xz

I installed on a 8 gigabyte SD card that revealed itself as /dev/disk1 using this diskutil command (via osx – List all devices connected, lsblk for Mac OS X – Ask Different [WayBack])

diskutil list

So this wrote the image to SD card in a sudo su - prompt:

targetDevice="disk2"
unxz --keep openSUSE-Tumbleweed-ARM-JeOS-raspberrypi2.armv7l-2016.08.20-Build2.1.raw.xz; \
diskutil umount "/dev/${targetDevice}s1"; \
dd bs=1m of="/dev/r${targetDevice}" if=openSUSE-Tumbleweed-ARM-JeOS-raspberrypi2.armv7l-2016.08.20-Build2.1.raw; \
sync; \
diskutil list; \
diskutil eject "/dev/${targetDevice}"

or if you want to select which image to “burn”:

targetDevice="disk2"
imageName="openSUSE-Tumbleweed-ARM-JeOS-raspberrypi2.armv7l-2016.08.20-Build2.1.raw"
imageName="openSUSE-Tumbleweed-ARM-JeOS-raspberrypi.armv6l-2016.11.23-Build2.22.raw"
imageName="openSUSE-Tumbleweed-ARM-JeOS-raspberrypi3.aarch64-2017.01.12-Build3.2.raw"
unxz --keep ${imageName}.xz; \
diskutil umount "/dev/${targetDevice}s1"; \
dd bs=1m of="/dev/r${targetDevice}" if=${imageName}; \
sync; \
diskutil list; \
diskutil eject "/dev/${targetDevice}"

A few notes:

Read the rest of this entry »

Posted in *nix, Development, Hardware, Hardware Development, Linux, Odroid, openSuSE, Power User, Raspberry Pi, Single-Board Computers, SuSE Linux, Tumbleweed | 1 Comment »

Some links I’ll need for monit one day

Posted by jpluimers on 2017/02/17

Getting monit to run on opensuse isn’t a feat.

I might try again one day with these links:

–jeroen

Posted in *nix, Linux, openSuSE, Power User, SuSE Linux, Tumbleweed | Leave a Comment »

Casting the audio of application on your Linux machine via Chrome to a ChromeCast

Posted by jpluimers on 2017/02/06

Hopefully by now mkchromecast [WayBack] works on more Linux versions (and maybe even Mac OS X is better supported [WayBack]), but back then it was only available for Ubuntu 16.10 and up:

Do you want to stream the audio from Rhythmbox, VLC or another Linux app to your TV through Chromecast? Well, we’ve found a nifty little Linux tool that lets you do just that.

Source: How to Send Your Linux Desktop Audio to a Chromecast – OMG! Ubuntu!

The tool is at github: Linux · muammar/mkchromecast Wiki  [WayBack]: mkchromecast – Cast macOS, or Linux Audio to your Google Cast Devices

–jeroen

via:

Posted in *nix, Chrome, Chromecast, Google, Linux, Power User, Ubuntu | Leave a Comment »