If you only want to change the settings for yourself, then edit them locally, NOT in the system-wide files, e.g.:
$ cat .bash_profile ... export PAGER='less --quit-if-one-screen --quit-at-eof --jump-target=2 --ignore-case ' PATH=~/bin:${PATH} ~mark From: "Gary Turner" <[EMAIL PROTECTED]> > This looks to be just what I need. Presumeably I can define CLASSPATH > and PYTHONPATH et al. in the same file.