My Confusion About the Path Variable

This is a topic that I should have understood a long time ago, but I never really thought about it until I printed out my PATH variables. The horror of the output made me realize that I am on an unholy path, meaning there were several duplicated entries.

The reason for this is that I exported the PATH variable in my .bashrc file. The rc file is read every time a new terminal session is started, so the additional PATH values will be appended every time.

The proper place for PATH variables would be the .profile file (there are other options depending on the interactive shell, for example, .bash_profile and .bash_login). This file is read only once when the user logs in.

For clarification, the order and the precedence of the files are the following in my case:

• /bin/bash - shell executable
• /etc/profile - system wide, executed for login shell
• ~/.profile - personal, executed for login shell
• ~/.bashrc - personal, executed for interactive non-login shell

But there is a catch. I use .bashrc because it’s portable, but I did not want to do the same with .profile because that could contain machine specific instructions. (And I don’t want to maintain a shell-specific profile file like .bash_profile either).

Time for a good old compromise. With the help of some bashism (provided by interweb surfing), I remove the value before I add it.

# method for removing a path from the PATH variable
pathremove() {
  PATH=${PATH//:"$1:"/:}
  PATH=${PATH/#"$1:"/}
  PATH=${PATH/%":$1"/}
}
export pathremove

# method for adding a path to the PATH variable
pathprepend() {
  for arg in "$@"; do
    pathremove "$arg"
    export PATH="$arg${PATH:+":${PATH}"}"
  done
}
export pathprepend

# Adding local bin and personal scripts to the PATH variable
pathprepend \
  "$HOME/.local/bin/toolbox" \
  "$HOME/.local/bin"

Following this logic I can prioritize my own paths over the system paths. This is a good way to keep the PATH variable clean and tidy, even if it means this has to run every time I start a new session.