I am trying to install tomcat 8 on centos 7.  I am using the terminal as root.  When I type in source ~/.bashrc, the terminal gives back the following error: -bash: unalias: ls: not found.  How can I resolve this error so that the source ~/.bashrc command can succeed? Note that I recently added the line unalias ls as the last line of ~/.bashrc as per @Cyrus' solution to this other problem related to color aliasing in the same CentOS installation.
-bash: unalias: ls: not found
bash;alias
I can't reproduce this but I assume the problem is because you have already unaliased ls once, so you can't unalias it again. However, I'm also pretty sure that the source command worked perfectly. Did you check? Chances are that it was sourced correctly and you can just ignore the error message. More to the point, why are you running source ~/.bashrc? That file should be read when you start a new interactive non-login shell anyway. If it's to reload it because you made a change, then you're fine, your change was loaded. Ignore the error.