Is it safe to run these instructions as a root user? I have CentOS and I want install `scala` by: Installing `scala` on CentOS. I want to ask if it's safe installing this as root user? The commands are: wget tar xvf scala-2.10.1.tgz sudo mv scala-2.10.1 /usr/lib sudo ln -s /usr/lib/scala-2.10.1 /usr/lib/scala export PATH=$PATH:/usr/lib/scala/bin scala -version

It depends. From the instructions, it looks like it won't harm your PC, but we don't know what's inside the tar. However, the command set doesn't contain anything explicitly malicious.

So, from non-paranoid point of view: yeah, it should be safe.