Customizing Your Terminal¶

Config Files¶

The main file to edit to customize the terminal is ~/.bashrc.
This will be run on every interactive login shell (for the specific user).

If you want to customize a certain thing for all users, there are some global files you can edit.

`~/.bashrc`¶

This is the runtime configuration file for bash, and it will be executed every time a new interactive shell is loaded.
Put any valid bash/sh code in here and it will be executed when bash starts interactively.

`/etc/profile` and `~/.bash_logout` (system-wide `.bashrc`)¶

The /etc/profile file is loaded on every single instance of bash, whether it's a login/interactive shell or not.
It's basically a system-wide .bashrc file.

If /etc/profile exists, it will read/execute this first, before any other config files.
Then bash will look for ~/.bash_profile, ~/.bash_login, and ~/.profile.
The first one of these found will be read/executed, and the rest will be ignored.

The ~/.bash_logout file will be read/executed every time a shell exits (with the exit builtin), whether it's a login/interactive shell or non-interactive shell.

So the order in which bash loads config files:

Non-interactive
- /etc/profile (always)
- First one found (in this order):
  - ~/.bash_profile
  - ~/.bash_login
  - ~/.profile
- ~/.bash_logout when the shell exits.
Interactive shell
- /etc/profile (always)
- /etc/bash.bashrc (always)
- First one found (in this order):
  - ~/.bash_profile
  - ~/.bash_login
  - ~/.profile
- ~/.bashrc
- ~/.bash_logout when the shell exits.

Colors¶

See ANSI escape sequences for more details.

30 - 37 : 8-color foreground colors.
40 - 47 : 8-color background colors.
38;5;0 - 255 : 88/256-color foreground colors.
48;5;0 - 255 : 88/256-color background colors.

Customizing Your Prompt¶

Modify the PS1 Environment Variable¶

PS1 is the environment variable that controls what the terminal prompt looks like.

Here is a list of special escape sequences
available for use in PS1.

These can also be found in man://bash, /^\s*PROMPTING.

Escape Sequence	What it Represents
`\a`	ASCII bell character (audio bell/visual bell on some terminals)
`\d`	Date in "Weekday Month Date" format (e.g., "Tue May 26")
`\D{format}`	Custom date format, using strftime format specifiers.
`\e`	ASCII escape character
`\h`	Hostname up to the first `.`
`\H`	Full hostname
`\j`	Number of jobs currently managed by the shell
`\l`	Basename of the shell’s terminal device name
`\n`	Newline
`\r`	Carriage return
`\s`	Name of the shell (e.g., "Bash")
`\t`	Current time in 24-hour HH:MM:SS format
`\T`	Current time in 12-hour HH:MM:SS format
`\@`	Current time in 12-hour am/pm format
`\A`	Current time in 24-hour HH:MM format
`\u`	Username of the current user
`\v`	Version of Bash (e.g., 4.4.19)
`\V`	Version of Bash + patch level (e.g., 4.4.19.1)
`\w`	Current working directory (full path)
`\W`	Basename of the current working directory
`\!`	History number of this command
`\#`	Command number of this command (counts each command)
`\$`	If the current user's UID is 0 (root user), a `#`, otherwise a `$`
`\nnn`	Character represented by the octal value nnn
`\[`	Marks the start of a sequence of non-printing characters (colors, etc)
`\]`	Marks the end of a sequence of non-printing characters

Any ANSI color control sequences need to be wrapped in \[ and \]:

export PS1="\[\e[38;5;20m\]\u:\h \$ \[\e[0m\]"  
            #256-color ANSI         # Reset

See ANSI control sequences for adding colors.

\w (The current working directory), uses the value of the PROMPT_DIRTRIM variable.
- If set, it will use this number as the number of trailing directories to keep.

Modifying the PS2 Environment Variable¶

PS2 is the environment variable that controls what the next-line prompt looks like.

For example when running:

user@server $ command "argument" \
> "another argument"  
> "The > is the ${PS2} environment variable"

In this instance, PS2="> ".

If your PS2 variable was set to ~>, it would show those characters on newlines within commands:

user@server $ command "argument" \
~> "another argument"  
~> "The > is the ${PS2} environment variable"