What goes into a shell startup file? Some things may seem obvious, such as the path and a prompt setting. But wait, what exactly should be in the path, and what does a reasonable prompt look like? And how much is too much to put in a startup file?
The next few sections outline the essentials of a shell startup file, covering the command path, manual page path, prompt, aliases, and permissions mask.
The most important part of any shell startup file is the command path. The path should cover the directories that contain every application of any general interest to a regular user. At the very least, the path should contain these components, in this order:
/usr/local/bin /usr/bin /usr/X11R6/bin /bin
This order ...