bash-basic-command-palette

A command palette that works from bash 3.2 using only builtins and tput

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I've seen a couple of other command palettes that looked really good and very full featured, but these either didn't work on older bash, or needed some other dependencies, which, when working on someone elses servers, aren't always possible to install.

It's a very basic model at the moment, and I intend to add some examples when I have the time, but presently I'm using this as a switcher for my tmux sessions to allow me to jump from host to host and I'd like to make a reverse-i-search replacement that allows the command palette style filtering.

Configuration

There are a few options that can be configured at the top of the script, but I do plan on moving this to a config file if it's actually a useful tool.

Usage

command-palette <action> <list option> [<list option>, ...]
command-palette "<list options separated by newlines>"

So something like:

command-palette eval "$(history | tail | cut -c8-)"

would give you an excerpt of your history that is easily searchable.

If you provide a string that contains newlines, that item will be split on newlines into individual options, you can also just supply a list of arguments. To preserve spaces in items, use quotes, or escape them:

command-palette echo Item 1 "Item 2" Item\ three 'Item 4'

produces:

 |    
 * Item   
   1   
   Item 2   
   Item three   
   Item 4   

The default <action> is to call echo.

Config file

After setting up the defaults, the script looks for ~/.command-palette.conf, if it exists it would be sourced allowing the config file to directly overwrite the variables defined before it's included. This includes:

• styleReset - This would probably be bad to overwrite, but this defines the sequence for resetting the terminal after adding styling.

• styleListItemStart - This is prepended to listItemPrefix to enable styling. These exist as separate variables so that their length isn't counted when calculating what will and won't fit on screen.

• styleListItemEnd - This is appended to listItemSuffix.

• styleListItemSelectedStart - This is prepended to listItemPrefixSelected.

• styleListItemSelectedEnd - This is appended to listItemSuffixSelected.

• styleTitleStart - This is prepended to the title.

• styleTitleEnd - This is appended to the title.

• listItemPrefix - This is prepended to the list item. Default:    .

• listItemSuffix - This is appended to the list item. Default:    .

• listItemPrefixSelected - This is prepended to the selected list item. Default:  * .

• listItemSuffixSelected - This is appended to the selected list item. Default:    .

• listItemEllipsis - This is appended to any truncated list items. Default: ....

• titlePrefix - This is prepended to titlePrefix. Default: <empty>;

• titleSuffix - This is appended to titlePrefix. Default: <empty>;

• searchPrefix - This is prepended to the search filter. Default:  | .

• searchSuffix - This is appended to the search filter. Default: <empty>.

Command-line Options

• (-a |--action |--action=)<action> - Explicitly sets the action when selecting a menu item.
• (-f |--filter |--filter=)<filter> - Prefill the filter.
• -h|--help - Show help.
• -k|--keep-open - Keep command-palette open after running action
• (-t |--title |--title=)<title> - Add an optional title.

Keyboard Shortcuts

When in the command-palette interface, Esc BkSp will clear the filter, and you can use Esc Esc to quit without executing <action>. When navigating the list, the ↑ and ↓ arrows move up and down the list, PgUp and PgDn move up or down half a screen of items, and Home and End move to the beginning and end of the list respectively.

Writeup

I've created a blog post about my motivation for building this and the steps to build the basic version for anyone interested in making something similar. Hopefully it'll be helpful to someone!

TODO

• Default action
• Option to prefill the filter
• Add an optional title
• Add a config file
• Sorting
• Add left/right support for long lines
• Intelligent screen repainting
• Multi-select
• Accept a pipe (need to differentiate pipe input and subsequent key input via read...)