Bash is the default shell on Debian. When you log in, bash reads /etc/profile (system-wide) and ~/.bashrc (user-specific) to set up your environment. Add commands and variables to ~/.bashrc to customize your shell.

$ echo $SHELL                   # current shell
$ chsh -s /bin/bash             # change default shell (on next login)
$ cat ~/.bashrc                 # view bash configuration
$ source ~/.bashrc              # reload configuration

Environment variables are inherited by child processes. Set them in ~/.bashrc or ~/.bash_profile:

export PATH=$PATH:~/.local/bin  # add directory to PATH
export EDITOR=vim               # set default editor
export PS1='\u@\h:\w$ '         # customize prompt

Common variables:

• $PATH — directories searched for executables (colon-separated)
• $HOME — user's home directory
• $USER — current username
• $SHELL — current shell
• $EDITOR — default text editor
• $LANG, $LC_* — language and locale settings

Tip: If you add to $PATH, put user directories (~/.local/bin) before system directories to override installed programs locally.