Startup Sequences of Shells

It is quite confusing if you need to work with multiple, so I make following tables.

zsh

From section STARTUP/SHUTDOWN FILES of man page zsh

Interactive Login	Non-Interactive Login	Interactive Non-Login	Non-Interactive Non-Login
/etc/zshenv $ZDOTDIR/.zshenv
/etc/zprofile $ZDOTDIR/.zprofile		–
/etc/zshrc $ZDOTDIR/.zshrc	–	/etc/zshrc $ZDOTDIR/.zshrc	–
/etc/zlogin $ZDOTDIR/.zlogin		–

bash

From section INVOCATION of man page bash

default

Interactive Login	Non-Interactive Login	Interactive Non-Login	Non-Interactive Non-Login
/etc/profile Then the first one that is readable amongst: ~/.bash_profile ~/.bash_login ~/.profile		~/.bashrc	$BASH_ENV

bash as sh

Interactive Login	Non-Interactive Login	Interactive Non-Login	Non-Interactive Non-Login
/etc/profile ~/.profile		–
$ENV	–	$ENV	–

tcsh

tcsh does not seem care the interactive mode when start up. if environment version has lf, then csh.login and ~/.login will run before csh.cshrc and ~/.tcshrc, respectively.
From section Startup and shutdown of man page tcsh

Login	Non-Login
/etc/csh.cshrc
/etc/csh.login	–
First one that is readable amongst: ~/.tcshrc ~/.cshrc
~/.history ~/.login ~/.cshdirs	–