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  • Jay Versluis 10:01 am on April 13, 2015 Permalink | Reply  
    Categories: Announcements, Linux ( 7 )

    LAMP Stack for Humans – now available on Amazon 

    Lampstack-SoftcoverMy book LAMP Stack for Humans is now available on Amazon. It this 284 page guide I’ll walk you through the process of turning an old laptop into an always-on server. You can use it to run web applications in the comfort of your own home or office – no “cloud” required.

    Together we will configure the entire server: you will learn how to install CentOS, Apache, PHP and MySQL (or MariaDB) and WordPress. I will show you how you can reach your server from other computers on the network and how to create regular backups.

    Perfect for the Linux newbie and those who want to get started with web applications without spending money “in the cloud” (in my opinion THE WORST expression for describing remote computers).

    If you’re an avid reader of this site and have always wished that some instructions would be presented in a more cohesive form rather than in snippets, then LAMP Stack for Humans is perfect for you.

     

    Grab your free sample today, or read the entire book for free via Kindle Unlimited!

     

     
    • Falkon 2:28 am on October 21, 2015 Permalink | Reply

      Hi Jay
      I have a question regarding WP adding a Landing page for an existing site, meaning to add a new page which only displays a big logo in the start and be able to make that logo a roleover logo, and then the click would navigate a user to the main ( index page) if you will. i am new to WP and PHP wise I am still learning so I would not know how to add an extra page as the index page and the first index page turns say into a home.html. How would you do that? I trying to learn PHP and WP to what I work with in HTML & CSS and front end designs.
      Beforehand allow me to thank you for you time, help and assistance,

      Best Regards
      Falkon

      • Jay Versluis 2:55 pm on October 21, 2015 Permalink | Reply

        Hi Falkon, that’s a VERY off-topic question for this post…

        WordPress does have a way to display a static page as front page, instead of the default blog posts. You can change it like this:

        • for the blog, create a new page with a title (no content is necessary)
        • head over to Settings – Reading
        • under Front Page Displays, select your pages
        • hit Save and refresh the front page

        As for the roll-over image: insert an image into your static front page, then link that image to wherever you want (you can do that with Add Media from the page creation dialogue).

        Hope this helps!

  • Jay Versluis 9:53 am on December 3, 2016 Permalink | Reply
    Tags:   

    Categories: Plesk, Screencast, WordPress ( 68 )

    How to install a free SSL Certificate in Plesk Onyx 

    In this video I’ll explain how to add a free SSL Certificate for web traffic in Plesk Onyx.

    First we’ll enable the Let’s Encrypt extension in Plesk, then we’ll create the certificate and prepare our subscription for SSL traffic. And finally, we’ll tweak two values in the WordPress database so that all requests will be directed to https rather than http.

    Note that Let’s Encrypt SSL Certificates can only be used to encrypt web traffic between your server and a client’s browser. They cannot currently be used to secure email or Plesk itself (but who knows what the future holds).

    Enjoy!

     
  • Jay Versluis 10:06 am on December 2, 2016 Permalink | Reply
    Tags:   

    Categories: Linux ( 84 )

    How to print the current date and time in BASH shell scripts 

    Sometimes it’s useful to print the current time and date in a BASH script. We can make use of the date command for that. By default, and if called without any parameters, it’ll print something like this:

    echo $(date)
    Tue 29 Nov 2016 23:08:10 EST

    We can shorten this to just the date by using a formatting shortcut like this:

    echo $(date +"%x")
    29/11/2016

    or just the time using this format:

    echo $(date +"%r")
    11:09:26 pm

    Formatting shortcuts can also be used together, like so:

    $(date +"%x %r")
    29/11/2016 11:03:44 pm

    For a complete list of shortcuts, try “man date” from the command line.

     
  • Jay Versluis 10:52 am on December 1, 2016 Permalink | Reply
    Tags:   

    Categories: Linux ( 84 )

    How to use functions in a BASH shell script 

    BASH can deal with simple functions, and they are defined like this:

    # this defines the function
    function testing {
        echo "Hi there!"
    }
    
    # this calls our function
    testing

    As far as I know, BASH functions cannot take or return parameters.

     
  • Jay Versluis 10:45 am on November 30, 2016 Permalink | Reply
    Tags:   

    Categories: Linux ( 84 )

    How to use variables in a BASH shell script 

    Here’s how to use simple variables in BASH shell scripts. It appears there are no data types, and everything’s a string (correct me if I’m wrong). We can define a variable by first setting it to a value, then later refer to that value with a dollar sign in front of the variable name.

    Here’s an example:

    #!/bin/bash
    
    VARIABLE="Testing"
    echo $VARIABLE

    Note that there are no spaces between the variable name, the equal sign or the value. Adding those will result in a runtime error.

    Variables can be defined in upper or lower case letters, or a combination thereof.

    BASH Variables have a global scope, unless they are prefaced with the local keyword inside functions (in which case, only said function will have access to its value).

     
  • Jay Versluis 10:44 pm on November 29, 2016 Permalink | Reply
    Tags:   

    Categories: Linux, PHP ( 84 )

    How to install PHP from source on CentOS 

    PHP-IconI have recently installed PHP 7 from source on a fresh minimal CentOS 7 box. No previous version of PHP was installed, and I thought I’d give 7 a spin. There were a few pitfalls I hadn’t come across before, so here’s what worked for me.

    Downloading and extracting the source code

    It sounds crazy, but this was the hardest part of the whole installation! There were two problems I’ve encountered here.

    The first was that PHP offer downloads via a mirror. A direct link may look something like this: http://php.net/get/php-7.0.12.tar.bz2/from/this/mirror. This means that if we were to download this file using wget, it would be saved as “mirror”. Now what we want.

    So instead we can ask wget to give the download a different name using the -O parameter, like so:

    wget -O php7.tar.bz2 http://php.net/get/php-7.0.12.tar.bz2/from/this/mirror

    This will save our file as php7.tar.bz2 instead. So far so good. Unpacking this file seems to be impossible. From what the internet tells me, this should be the correct way of extracting a tar.bz2 file:

    tar -jxvf php7.tar.bz2

    But that didn’t work, not matter how hard I tried. All I ever got was a “non-recoverable” error. Which sucks. In the end I extracted the file on my Mac, created a ZIP archive and downloaded that instead. Unnecessarily cumbersome and idiotic, but worked. Finally I had them on my CentOS box.

    Building the source code

    Jumping into the extracted directory, the configure command can prepare the build. At this stage I encountered an error:

    configure: error: xml2-config not found. Please check your libxml2 installation.

    This can be fixed by installing the libxml2-devel package (NOT libxml2 as the error would have you believe). Let’s do that and run configure again:

    yum install libxml2-devel
    ./configure

    Now we can run make, followed by make test to see if the installation is going to go well. This will take a few minutes.

    make
    make test

    Feel free to skip “make test” if you’re in a hurry. In my case, after over 10.000 tests, PHP told me this:

    You may have found a problem in PHP.
    This report can be automatically sent to the PHP QA team at
    http://qa.php.net/reports and http://news.php.net/php.qa.reports
    This gives us a better understanding of PHP's behavior.
    If you don't want to send the report immediately you can choose
    option "s" to save it. You can then email it to qa-reports@lists.php.net later.

    Perplexed yet unfazed, I continued on and installed PHP anyway:

    make install

    And only moments later, PHP 7 was running on my CentOS system.

    php -v
    
    PHP 7.0.12 (cli) (built: Nov  8 2016 06:59:14) ( NTS )
    Copyright (c) 1997-2016 The PHP Group
    Zend Engine v3.0.0, Copyright (c) 1998-2016 Zend Technologies

    Not sure what else to tell you.

     
  • Jay Versluis 9:53 am on November 11, 2016 Permalink | Reply
    Tags:   

    Categories: Linux, WordPress ( 84 )

    Upgrade Trouble: when WordPress is asking for FTP details, but there’s no FTP server on your system 

    wordpress-iconI was working on a CentOS 7 server the other day that had a LAMP stack installed. It was used to host only a single instance of WordPress.

    Upgrading themes and plugins from the admin interface worked fine, but curiously, WordPress core upgrades did not. Instead, WordPress was asking for FTP details every time, which also prevented auto upgrades from being installed.

    This didn’t make any sense because there was no FTP server installed on the box, nor had there ever been one. But it did indicate that WordPress had an issue with overwriting core files.

    The first thing I checked was that the /var/www/html directory had the correct file and ownership permissions. It all looked correct, even though I did manually set them again just to make sure. Without success. WordPress was still asking for FTP credentials.

    After some research, I found that there is a setting for how WordPress accesses the filesystem when it’s upgrade time. We can define it with a constant called FS_METHOD in wp-config.php. The ins and outs are explained in the codex, under Upgrade Constants:

    FS_METHOD forces the filesystem method. It should only be “direct”, “ssh2”, “ftpext”, or “ftpsockets”. Generally, you should only change this if you are experiencing update problems. If you change it and it doesn’t help, change it back/remove it. Under most circumstances, setting it to ‘ftpsockets’ will work if the automatically chosen method does not. Note that your selection here has serious security implications. If you are not familiar with them, you should seek help before making a change.

    • (Primary Preference) “direct” forces it to use Direct File I/O requests from within PHP. It is the option chosen by default.
    • (Secondary Preference) “ssh2” is to force the usage of the SSH PHP Extension if installed
    • (3rd Preference) “ftpext” is to force the usage of the FTP PHP Extension for FTP Access, and finally
    • (4th Preference) “ftpsockets” utilises the PHP Sockets Class for FTP Access.

    So on this particular server, for whatever reason, WordPress did not choose the first method (direct), even though it should have. Defining this constant manually did the trick, all I had to do was add this line to my wp-config.php file:

    // explicitly use direct mode and stop asking for FTP details
    define('FS_METHOD','direct');

    Now updates are working as expected. I’ve never seen this problem on LAMP stacks before. Guess you learn something new every day.

     
  • Jay Versluis 10:34 am on November 7, 2016 Permalink | Reply
    Tags:   

    Categories: Linux, Python ( 84 )

    How to install Python 3 from source in CentOS 

    python-logoCentOS 6 comes with Python 2.6 installed, and CentOS 7 comes with Python 2.7. But right now, Python 3.5 is all the rage, so I thought I’d install it alongside Python 2.x on the same machine.

    Here’s how I did it.

    I’m using a CentOS 6 32 bit system here, but I’ve tried the same on a CentOS 7 64 bit rig. You need to be root or have superuser privileges to do this successfully. (More …)

     
  • Jay Versluis 11:19 am on November 6, 2016 Permalink | Reply
    Tags:   

    Categories: Linux ( 84 )

    How to extract tar.xz files on CentOS 

    CentOS-LogoI’ve recently come across a tarsal files that used xz compression (namely the Python source code).

    This means that my usual way of extracting a tarsal via the command line using the following command did not work:

    tar -zxvf Python*
    
    gzip: stdin: not in gzip format
    tar: Child returned status 1
    tar: Error is not recoverable: exiting now

    That had me stumped! Turns out that files with a tar.gz ending can be extracted this way (because the use gzip compression, specified by the z parameter). If tar is instructed to use this format on a tar.xz file, it fails.

    The solution: specify the xz compression, using the capital letter J, like this:

    tar -Jxvf Python*
    [massive list of files goes here]

    Another Linux mystery solved – thanks to Justin Solver for this tip!

     
  • Jay Versluis 11:06 am on November 5, 2016 Permalink | Reply
    Tags: Logitech   

    Categories: Mac OS X, Windows ( 30 )

    How to fix problems with Logitech Unifying Receivers 

    screen-shot-2016-11-04-at-17-12-10I’ve recently bought a new Logitech K360 keyboard for my HP Z600 workstation. I also had a Logitech M325 mouse, both of which came with Unifying USB receivers. I could plug both receivers in, and both devices would work great.

    However, I heard great things about these little receivers and wanted to free up a USB port, and thought I’d connect both devices to the same receiver. Apparently you can connect up to 6 devices to one receiver and store any spare ones inside the mouse or keyboard. Being an all-efficient belt-and-braces kinda guy, I tried my luck.

    Turns out it was relatively easy to pair both devices to the same receiver, thanks to a small piece of software that can be found here, along with instructions on how to use it:

    It all worked fine on my Windows 10 machine, until I wanted to use the mouse (not the keyboard) with my Mac. I know, it’s exotic, and perhaps I should have just bought another mouse. But really, there’s only so much space on my desk, and I really don’t need more clutter in front of me for just an occasional switch.

    I regretted pairing both devices to the same receiver and wished I hadn’t done that, for this very eventuality. So now I had to figure out how to UN-pair both devices again and put them back to how things used to be (before I started messing with them). (More …)

     
  • Jay Versluis 10:54 am on November 4, 2016 Permalink | Reply  
    Categories: Mac OS X, Screencast ( 30 )

    How to launch a Mac App with Command Line Parameters from the Dock 

    In this video I’ll show you how to launch a Mac App from the Command Line, so that we can pass parameters. I’ll also explain how to wrap up such a command into your own app and add an icon to it, so that you can launch it from the dock with a single click.

    This can be useful if you need to convince Google Chrome or any other app to launch with certain parameters and modify its behaviour somehow. In my example I’m using Blender, and I’m using a startup parameter to change its default render engine upon launch. The same principles apply to any app you need to launch with startup parameters.

    The process is as follows:

    • find out the full path of the app you want to launch
    • try launching your app from the command line
    • now add parameters to the end of the launch command
    • create an Automator App
    • change its icon from from the generic Otto Icon to your desired app’s icon
    • drag your new launcher app into the dock

    I’ll explain all the gory details in this video.

    Enjoy!

     
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