Unable to install Snap7 Library on Ubuntu 16.04 (64-bit)
<p>I'm new to Linux based OS's (and very new to Snap7).
Trying to install Snap7 library on Ubuntu machine following instructions at - <a href="http://python-snap7.readthedocs.io/en/latest/installation.html" rel="nofollow">http://python-snap7.readthedocs.io/en/latest/installation.html</a>. However I'm getting the following errors during the 3rd step</p>

<pre><code>E: Unable to locate package libsnap71
E: Unable to locate package libsnap7-dev
</code></pre>

<p>I'm not sure how exactly to manually install it and I'm unsure how to fix this installation issue so any advice whould be fantastic :)</p>

<p>Below is a copy of the log after already running the "add repository" command:</p>

<pre><code>administrator@*pc-name*:~/Documents/*folder*$ sudo apt-get update
Hit:1 http://au.archive.ubuntu.com/ubuntu xenial InRelease
Get:2 http://au.archive.ubuntu.com/ubuntu xenial-updates InRelease [95.7 kB]   
Hit:3 http://au.archive.ubuntu.com/ubuntu xenial-backports InRelease           
Get:4 http://au.archive.ubuntu.com/ubuntu xenial-updates/main amd64 DEP-11 Metadata [299 kB]
Ign:5 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial InRelease         
Get:6 http://security.ubuntu.com/ubuntu xenial-security InRelease [94.5 kB]    
Get:7 http://au.archive.ubuntu.com/ubuntu xenial-updates/main DEP-11 64x64 Icons [184 kB]
Ign:8 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial Release           
Ign:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Ign:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Err:9 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 Packages
  404  Not Found
Ign:10 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main i386 Packages
Ign:11 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main all Packages
Ign:12 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en_AU
Ign:13 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial/main DEP-11 64x64 Icons
Fetched 673 kB in 13s (50.9 kB/s)
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/gijzelaar/snap7/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch http://ppa.launchpad.net/gijzelaar/snap7/ubuntu/dists/xenial/main/binary-amd64/Packages  404  Not Found
E: Some index files failed to download. They have been ignored, or old ones used instead.
administrator@*pc-name*:~/Documents/*folder*$ sudo apt-get install libsnap71 libsnap7-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package libsnap71
E: Unable to locate package libsnap7-dev
</code></pre>

<p>Please let me know if you need more information to make a proper assessment.</p>

<p>You missed this part on the very page you linked to:</p>

<pre><code>If you are using Ubuntu you can use the Ubuntu packages from our launchpad PPA.
To install:

$ sudo add-apt-repository ppa:gijzelaar/snap7
$ sudo apt-get update
$ sudo apt-get install libsnap71 libsnap7-dev
</code></pre>

<p>Execute all three commands in order and you should be fine. <em>However</em>, as the software is older than your system, you need to edit the <code>/etc/apt/sources.d</code> file created after the first step and replace <code>xenial</code> (or even <code>yaketty</code>) with <code>trusty</code>.  The ppa only has builds for older releases.</p>

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