Ubuntu – .profile and .bash_profile ignored when starting tmux from .bashrc

Traditionally, when you log into a Unix system, the system would start one program for you. That program is a shell, i.e., a program designed to start other programs. It's a command line shell: you start another program by typing its name. The default shell, a Bourne shell, reads commands from ~/.profile when it is invoked as the login shell.

Bash is a Bourne-like shell. It reads commands from ~/.bash_profile when it is invoked as the login shell, and if that file doesn't exist¹, it tries reading ~/.profile instead.

You can invoke a shell directly at any time, for example by launching a terminal emulator inside a GUI environment. If the shell is not a login shell, it doesn't read ~/.profile. When you start bash as an interactive shell (i.e., not to run a script), it reads ~/.bashrc (except when invoked as a login shell, then it only reads ~/.bash_profile or ~/.profile.

Therefore:

• ~/.profile is the place to put stuff that applies to your whole session, such as programs that you want to start when you log in (but not graphical programs, they go into a different file), and environment variable definitions.

• ~/.bashrc is the place to put stuff that applies only to bash itself, such as alias and function definitions, shell options, and prompt settings. (You could also put key bindings there, but for bash they normally go into ~/.inputrc.)

• ~/.bash_profile can be used instead of ~/.profile, but it is read by bash only, not by any other shell. (This is mostly a concern if you want your initialization files to work on multiple machines and your login shell isn't bash on all of them.) This is a logical place to include ~/.bashrc if the shell is interactive. I recommend the following contents in ~/.bash_profile:

  if [ -r ~/.profile ]; then . ~/.profile; fi
  case "$-" in *i*) if [ -r ~/.bashrc ]; then . ~/.bashrc; fi;; esac
  

On modern unices, there's an added complication related to ~/.profile. If you log in in a graphical environment (that is, if the program where you type your password is running in graphics mode), you don't automatically get a login shell that reads ~/.profile. Depending on the graphical login program, on the window manager or desktop environment you run afterwards, and on how your distribution configured these programs, your ~/.profile may or may not be read. If it's not, there's usually another place where you can define environment variables and programs to launch when you log in, but there is unfortunately no standard location.

Note that you may see here and there recommendations to either put environment variable definitions in ~/.bashrc or always launch login shells in terminals. Both are bad ideas. The most common problem with either of these ideas is that your environment variables will only be set in programs launched via the terminal, not in programs started directly with an icon or menu or keyboard shortcut.

¹ _{For completeness, by request: if .bash_profile doesn't exist, bash also tries .bash_login before falling back to .profile. Feel free to forget it exists.}

Your shell, per se, doesn't have a "theme".

The shell itself is more or less just the command prompt and the functions behind that. Every other color information will be determined by other programs. For example, the LSCOLORS you found is an environment variable for the ls builtin to use these colors in its output instead of plain text. Similarly, vim also just outputs certain color based on its scheme.

The programs will use color codes for that. These are "escape sequences". For more info, see: Bash Prompt HOWTO: Chapter 6. ANSI Escape Sequences: Colours.

But the main point where you set how these colors are interpreted is your terminal, not your shell. So if at all, you should find themes for your terminal. You could then modify that when ls would output "red", you'll actually want "aubergine" or similar. Any terminal emulator allows you to change the colors.

For example, using the Solarized theme in iTerm 2 for OS X, you can see that my "bright red" will actually turn dark orange, and my "black" is somewhat blueish:

Finally, Generic Colouriser is a program that will allow you to colorize (almost) any command's output – even for commands that usually don't use colors at all, like traceroute: