GadgetoPrompt, a useless, gimmicky prompt for Bash on Linux

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README.md

GPrompt - useless gimmicky prompt for Bash on Linux

GPrompt (short for GadgetoPrompt) is a gimmicky Bash prompt generator that displays sort-of-useful information. It only works on Linux because that's what I use. It adapts to the terminal's width, showing or hiding information depending on the conditions.

Features

GPrompt prompts may consist in one or two lines. The top line is separated in three areas (left, midddle and right), while the second line (the "input" line, where the cursor is) only has a single, left-aligned area. Each area may be configured to display information from one of the generators. In addition, the script may be configured to generate a terminal title and/or terminal icon title.

Session example

Themes

Unthemed (but using custom layout):

`ascii_yb` theme

`ascii_gyr` theme

`blocks_yb` theme

`blocks_gyr` theme

`powerline_yb` theme

This theme requires a Powerline font.

`powerline_gyr` theme

This theme requires a Powerline font.

Installing GPrompt

GPrompt may be installed either at the system level or on a per-user basis.

User installation

Copy the script and associated themes to your home directory.

mkdir -p ~/.local/share/gprompt/themes
cp gprompt.pl ~/.local/share/gprompt
chmod +x ~/.local/share/gprompt/gprompt.pl
cp themes/* ~/.local/share/gprompt/themes/

Add the following line to your ~/.bashrc:

eval "$($HOME/.local/share/gprompt/gprompt.pl init)"

System-wide installation

In the case of a system-wide installation, the script and associated themes must be copied to some shared location, e.g.

mkdir -p /usr/share/gprompt/themes
cp gprompt.pl /usr/share/gprompt
chmod +x /usr/share/gprompt/gprompt.pl
cp themes/* /usr/share/gprompt/themes/

Users may then use GPrompt by adding the following line to their ~/.bashrc files (it could also be added to /etc/skel/.bashrc or /etc/bash.bashrc):
```
eval "$(/usr/share/gprompt/gprompt.pl init)"
```

Configuration

GPrompt comes with a minimal (...-ish, this is a gadget after all) configuration that will work out of the box. However, it can be customised using both a system-wide configuration file and a per-user configuration file. Values set in a configuration files override values that were previously loaded, so it is possible to have a system-wide configuration that replaces most of the defaults and a per-user configuration that only overrides a few of the system-wide options. In addition, if the option is enabled from the configuration files, it is possible to override settings using environment variables.

The GPrompt configuration is a Perl hash reference, so the general syntax of the file goes something like this:

{
    'some_key' => 'some_value' ,
    'other_key' => [ 'list entry 1' , 'list entry 2' ] ,
}

In order to override a configuration entry using an environment variable, the variable must be named GPROMPT_ followed by the uppercase name of the configuration entry. If the configuration expects a list for the value in question, the value of the environment variable will be split using the comma character. If a table is expected, keys and values are expected to be separated by a colon.

export GPROMPT_LAYOUT_RIGHT=git,load
export GPROMPT_LAYOUT_THEME_OVERRIDES=bg_left:230,bg_right:230

Main configuration

The following variables control the configuration itself:

cfg_warn_files indicates that the script should emit warnings when a file (configuration or theme) cannot be loaded due to some error (0 or 1, default 1).
cfg_from_env disables or enables configuration overrides from environment variables (0 or 1, default 0).
cfg_sys_themes must list system-wide directories which may contain GPrompt themes (list; default /usr/share/gprompt/themes).
cfg_user_themes lists directories relative to the user's home which may contain GPrompt themes (list; default .local/share/gprompt/themes and .gprompt-themes).

The layout_* variables control the prompt's layout and general appearance:

layout_theme is the name of the theme to use. The default theme will be used if it contains an empty string.
layout_theme_overrides may contain local overrides to the theme's contents (table, empty by default).
layout_left, layout_right and layout_input configure the generators that will provide the contents of the top left, top center, top right and bottom left sections of the prompt. All 3 variables are lists of generator names; by default, the top bar is empty (the script does not render it) and the input prompt only uses the userhost and cwd generators, emulating a rather basic \u@\h:\w prompt.
layout_middle defines the generator from which the top middle section will be displayed. Background colors emitted by the generator are ignored. By default this entry contains an empty string.
layout_input_always determines whether the input line should be rendered even if no generators are specified (0 or 1, default 0).
layout_empty_line determines how the prompt handles printing an empty line before the prompt's top line.
- When set to 0, no extra line is drawn, and commands that do not end with an EOL will cause the prompt's first line to be displayed incorrectly.
- When set to 1, the prompt's top line will always be preceeded with an empty line.
- When set to 2, the prompt will be preceeded by an empty line unless it is being drawn on the terminal's first line.
- When set to 3, a newline will be added to the prompt if the last command's output didn't end with a newline.

The term_* variables control the prompt's ability to change the terminal's title and/or icon title:

term_set_title controls whether the title or icon title of the terminal should be changed. Possible values are 0 (no update), 1 (title), 2 (icon title), and 3 (both). By default, only the title is updated.
term_generators contains the list of generators that will produce the title string (unicode characters in the generators' output will be removed).
term_separator is a string that will be inserted between the various parts of the string.

Generators also require specific configuration variables. These are documented in the generators' sections below.

Theme files

Themes are also stored using Perl hashes. The file containing a theme x should be named x.pm and located in one of the configured theme directories.

The following entries are used by the script's core :

padding must contain a single character which is used for padding the top line's middle area, amongst other things.
transition may contain a list of up to 8 color indices which can be used when generating transition strings from templates.
5 entries control each section's appearance.
- The sections are identified by left, middle, right and input (top left, top middle, top right and bottom left, respectively).
- Each section uses the following entries (replacing ${section} with a section's identifier):
  - bg_${section} is the index of the background color of the section.
  - fg_${section} is the index of the foreground color of the section.
  - ${section}_prefix is the template for the prefix of the section.
  - ${section}_separator is the template for the separator that is inserted between generated areas in the section.
  - ${section}_suffix is the template for the suffix of the section.
bg_ps2 is the index of the background color of the secondary prompt.
ps2_suffix is the template for the suffix of the secondary prompt.

Templates are strings which may contain \bX and \fX escape sequences, where X is a single digit, and which modify the background or foreground colors, respectively. Values 0 and 1 correspond to the preceding and following background color indices, while values between 2 and 9 will refer to the contents of the transition list.

In addition to the entries above, theme definitions contain entries that are specific to the various generators. These entries are documented below.

A few special values can be used to simplify writing theme definitions.

The thref function may be used to copy values from other elements in the current theme definition, for example:
```
bg_left   => 1 ,
bg_middle => 2 ,
bg_right  => thref 'bg_left' , # Left/right always use the same bg color
```
The TERM_DEFAULT value may be used for either background or foreground color definitions. The terminal's default color will be used for the text in question.
The SECTION_DEFAULT value may be used in generator-specific definitions to indicate that the current section's foreground or background color should be used.

Generators

Current working directory

The cwd generator will output the current working directory. Its only configuration variable, cwd_max_width, indicates the maximal percentage of the terminal's width that the path may occupy before truncation occurs. The following theme entries are required:

cwd_trunc is the string that replaces the part of the path that is truncated when it is too long compared to the terminal's width.
cwd_fg_color and cwd_bg_color are the foreground and background color indices for the section.
cwd_missing_fg_color and cwd_missing_bg_color are the foreground and background color indices that will be used if the current directory is in fact missing.

Date/time

The datetime generator will output the current date, the current time, or both. It is controlled by the following configuration entries:

dt_show_date controls whether the date should be displayed.
dt_show_time controls whether the time should be displayed.
dt_date_fmt is a strftime format that will be used for the date.
dt_time_fmt is a strftime format that will be used for the date.

In addition, the following entries must be set in the theme:

dt_bg is the background color for the section.
dt_time_fg is the foreground color for the time.
dt_date_fg is the foreground color for the date.

Git information

The git generator is meant to display information about the Git repository the current directory is a part of. It is controlled by the following configuration entries:

git_branch_danger is a list of branch names that will cause the current branch to be displayed with the "danger" color set.
git_branch_warn is a list of branch names that will cause the current branch to be displayed with the "warning" color set.
git_detached_warning controls the color set that will be used when the head is detached: 0 for the normal set, 1 for the "warning" set and 2 for the "danger" set.
git_show_status controls whether the status of the current repository should be displayed.
git_show_stash controls whether the stash depth should be displayed.

The theme entries belowed control the Git information sections' appearance:

git_branch_symbol is the prefix for the current branch's name.
The color sets for the branch display section are controlled by entries named git_branch_${set}_fg and git_branch_${set}_bg. The ${set} must be one of ok, warn or danger.
git_repstate_bg / git_repstate_fg are the colors of the section that indicates special states (e.g. rebase in progress, bare repository...)
git_status_pad is a string that will be inserted between the various parts of the status sections.
Two sets of entries control the sections that correspond to untracked and indexed changes. These sections are identified by replacing ${type} with either untracked and indexed in the names below.
- git_${type}_symbol is the prefix for the section's text,
- git_${type}_bg is the background color for the section,
- git_${type}_normal_fg is the foreground color for the normal text in the section,
- git_${type}_add_fg, git_${type}_mod_fg and git_${type}_del_fg define the foreground colors for the symbols that indicate new, modified or removed files, respectively.
git_add_symbol, git_mod_symbol and git_del_symbol define the symbols that indicate new, modified or deleted files in the status sections.
git_stash_symbol contains the prefix of the stash indicator,
git_stash_fg and git_stash_fg define the background and foreground colors for the stash indicator.

Running jobs

The jobs generator will output the amount of background jobs in the current shell. It is controlled by the following configuration variables:

jobs_always controls whether the job count should be displayed even when it is zero.

The following theme entries control how the jobs section is displayed.

jobs_prefix and jobs_suffix are the text of the prefix and suffix for the job count.
jobs_bg is the section's background color.
jobs_${element}_style and jobs_${element}_fg control the style and foreground color of the various parts of the section. ${element} may be:
- count for the count itself,
- prefix or suffix.

System load

The load generator will output the system's load average for the past minute divided by the host's processor count. It is controlled by the load_min configuration entry which specifies a percentage below which the section is not displayed at all. The following theme entries are required:

load_title is a string that is prepended to the generator's output.
load_low_fg and load_low_bg are the foreground and background colors used when the load is beneath 34%.
load_med_fg and load_med_bg are the foreground and background colors used when the load is between 34% and 66%.
load_high_fg and load_high_bg are the foreground and background colors used when the load is higher than 66%.

Previous command state

The prevcmd generator will output information about the previous command's return value. It is controlled by the following configuration entries:

pcmd_show_symbol controls whether a symbol that represents success or failure should be displayed.
pcmd_show_code controls whether the return value should be displayed. It can be set to the usual 0 and 1 values to disable/enable, or to 2 to enable only when the return value indicates failure.
pcmd_pad_code controls padding of the return value. 0 disables padding, 1 aligns to the left and -1 to the right. The global padding character is used.
pcmd_colors selects which parts of the output should use the theme's success or failure colors (0 nothing, 1 symbol, 2 value, 3 both).

The following theme entries are needed:

pcmd_ok_sym / pcmd_err_sym contain the symbols that represent success or failure, respectively.
pcmd_ok_fg and pcmd_ok_bg define the foreground and background colors used to represent success. The foreground color may or may not be used, depending on the configuration.
pcmd_err_fg and pcmd_err_bg define the foreground and background colors used to represent failure. The foreground color may or may not be used, depending on the configuration.
pcmd_text_fg controls the foreground color of the strings that are excluded from using success/failure colors by the configuration.

Python virtual environment

The pyenv generator will output the name of the currently active Python virtual environment if there is one. It is controlled by the following configuration entry :

pyenv_py_version controls how the Python version is displayed; it can be set to 0 (never display the Python version), 1 (display the Python version if a virtual environment is active) or 2 (always display the Python version).