This is a handy bash script to remove duplicate PATH directories but doesn't modify the order of the path already listed. Pretty cool idea.

Here is the url: remove duplicate dirs from PATH

Here is the code:

export PATH="$(echo "$PATH" | awk 'BEGIN{RS=":";}
{sub(sprintf("%c$",10),"");if(A[$0]){}else{A[$0]=1;
printf(((NR==1)?"":":")$0)}}')";

I try to put this towards the bottom of the .bash_profile file so that it is after any changes to the PATH environment variable.