I installed rbenv, a ruby version management program. I looked in the .bashrc file and noticed that the path variable was changed as below:

export PATH="$HOME/.rbenv/bin:$PATH"

I think the ":$PATH" part was included to include the old path contents. I would like to know what would happen if a program that modifies the path variable doesn't include the ":$PATH" part. Would I not be able to run some programs from the command line since the bin directories in which they reside are no longer included in the new path variable?