I was trying to append some text to multiple lines in vi on a RHEL 6 system, however I could not get it to work. I press Control + V to get into visual block mode, select the lines I need, but when I press capital A, instead of going into insert mode, it goes back into command mode. I then created two droplets on digital ocean to test this, one CentOS 7 and one Ubuntu, and to my surprise, this worked fine on Ubuntu, but did not on CentOS. So why is that? Is there some option I need to add to my vimrc file or are these functions remapped somehow on RHEL/CentOS? Searching the web did not help very much.