Merge pull request #83 from srl-wim/docs-improvements

added minor improvements to the installation.md

docs/install.md

@@ -1,12 +1,15 @@
-Containerlab is distributed as Linux package and can be installed on any Debian- or RHEL-like distributive.
+Containerlab is distributed as a Linux deb/rpm package and can be installed on any Debian- or RHEL-like distributive.
 
 ### Pre-requisites
-* Have `sudo` rights on the system: `containerlab` sets some parameters in the linux system to support the various options the containers need
+* Must be run as a root user or with `sudo`: `containerlab` sets some parameters in the linux kernel to support the various options the containers need
 * [Install docker](https://docs.docker.com/engine/install/): this is used to manage the containers
-* Import or Pull container images (e.g. Nokia SR-Linux, Arista cEOS) which are not online available for download from a registry. Containerlab will try to pull images if they do not exist on execution time.
+* Import or Pull container images (e.g. Nokia SR-Linux, Arista cEOS) which are not available downloadable from a container registry. Containerlab will try to pull images if they do not exist at run time.
 
 ### Package installation
-Containerlab package can be installed using the [installer script](https://github.com/srl-wim/container-lab/blob/master/get.sh) which detects the operating system type and installs the relevant package:
+Containerlab package can be installed using the [installation script](https://github.com/srl-wim/container-lab/blob/master/get.sh) which detects the operating system type and installs the relevant package:
+
+!!! note
+    Continarelab is distributed via deb/rpm packages, thus only Debian- and RHEL-like distributives are supported.
 
 ```bash
 # download and install the latest release
@@ -18,6 +21,15 @@ sudo curl -sL https://github.com/srl-wim/container-lab/raw/master/get.sh | \
 sudo bash -s -- -v 0.6.0
 ```
 
+### Upgrade
+To upgrade `containerlab` to the latest available version issue the following command:
+
+```
+containerlab version upgrade
+```
+
+This command will fetch the installation script and will upgrade the tool to its most recent version.
+
 ### Graphviz
 Containerlab's `graph` command can render a topology graph. For the generation of PNG images out of the topology files `graphviz` tool needs to be installed.
 
@@ -31,12 +43,3 @@ sudo yum install graphviz
 ```
 
 Note, that `graphviz` installation is optional and is only required when a user wants to generate PNG files on the system out of the generated `dot` files.
-
-### Upgrade
-To upgrade `containerlab` to the latest available version issue the following command:
-
-```
-containerlab version upgrade
-```
-
-This command will fetch the installation script and will upgrade the tool to its most recent version.