Shell startup files

Common

~/.profile

Ignored if ~/.bash_profile or ~/.bash_login exists.

The .profile file is read by the command interpreter for login shells. This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login exists.

this file is read and executed By bash or other shells when you login to your user account either by using the login screen or by using the terminal.

/etc/profile and /etc/profile.d/<YOUR_SCRIPT>.sh

Common initialization file read by all Bourne-compatible shells. This file (/etc/profile) should be kept as small as possible and only contain settings that are also valid for non-interactive shells.

If you want to add some startup script for all users, you can add it under /etc/profile.d directory. For example, you can add your script to set PATH environment variable.

~/.bash_profile

Bourne shell compatible initialization file read by Bash when started as a login shell (MUST be ~/.bash_profile, ~/.bashrc will not do, see below).

The personal initialization file, executed for login shells. This file is read-only when the shell is started to execute a command from the command line. Otherwise, bash reads it when it is invoked as a login shell. Is only read by Bash when started in interactive login mode.

Table of startup files by shell

Shell	File
Bash	~/.bash_profile ~/.bash_login ~/.profile
Zsh	~/.zprofile ~/.zlogin
Ksh	~/.profile
Fish	~/.config/fish/config.fish
Common	~/.profile /etc/profile /etc/profile.d/<YOUR_SCRIPT>.sh