How to do it...

This example shows how to add new paths to the beginning of an environment variable. The first example shows how to do this with what's been covered so far, the second demonstrates creating a function to simplify modifying the variable. Functions are covered later in this chapter.

export PATH=/opt/myapp/bin:$PATH 
export LD_LIBRARY_PATH=/opt/myapp/lib;$LD_LIBRARY_PATH

The PATH and LD_LIBRARY_PATH variables should now look something like this:

PATH=/opt/myapp/bin:/usr/bin:/bin 
LD_LIBRARY_PATH=/opt/myapp/lib:/usr/lib;/lib

We can make adding a new path easier by defining a prepend function in the .bashrc file.

prepend() { [ -d "$2" ] && eval $1=\"$2':'\$$1\" && export $1; }

This can be used in the following way:

prepend PATH /opt/myapp/bin 
prepend LD_LIBRARY_PATH /opt/myapp/lib