.profile

the configuration file (located in your home directory) that tells your shell how to behave; .profile will work for almost all shells. For more advanced shells (i.e., anything that's not the Bourne Shell,) it's usually set to redirect to the proper shell's .profile.

see also .shell_profile (e.g., .bash_profile)

an example of .bash_profile:

dave@samizdata:~% more .bash_profile
# ~/.bash_profile: executed by bash(1) for login shells.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package. 
# the default umask is set in /etc/login.defs
#umask 022  
# the rest of this file is commented out. 
# include .bashrc if it exists
if [ -f ~/.bashrc ]; then
    . ~/.bashrc
fi 
# set PATH so it includes user's private bin if it exists
if [ -d ~/bin ] ; then
    PATH=~/bin:"${PATH}"
fi
# do the same with MANPATH
#if [ -d ~/man ]; then
#    MANPATH=~/man:"${MANPATH}"
#    export MANPATH
#fi