.profile

the configuration file 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