Nushell Hacks

Listed below are the top nushell hacks that people often forget about or didn't know.

1. ends-with / starts-with operators

❯ ls | where name ends-with .toml or name starts-with Car
╭─#─┬────────name─────────┬─type─┬───size───┬────modified────╮
│ 0 │ Cargo.lock          │ file │ 165.4 KB │ 22 minutes ago │
│ 1 │ Cargo.toml          │ file │   6.4 KB │ an hour ago    │
│ 2 │ Cross.toml          │ file │    666 B │ an hour ago    │
│ 3 │ rust-toolchain.toml │ file │   1.1 KB │ an hour ago    │
╰───┴─────────────────────┴──────┴──────────┴────────────────╯

2. easter egg

Did you know that when you start nushell, the $env.CMD_DURATION_MS value of 0823 is an easter egg? It's nushell's first public release date month day.

3. abbr

With this menu and keybinding configured appropriately in your config.nu file, you can hit ctrl+space and your alias abbreviation will expand to it's non-abbreviated form.

For instance, if you have this alias

alias gwch = git whatchanged -p --abbrev-commit --pretty=medium

and then you type gwch<ctrl+space> it will expand on the prompt line to

git whatchanged -p --abbrev-commit --pretty=medium

keybinding

  {
    name: abbr
    modifier: control
    keycode: space
    mode: [emacs, vi_normal, vi_insert]
    event: [
    { send: menu name: abbr_menu }
    { edit: insertchar, value: ' '}
    ]
  }

    {
      name: abbr_menu
      only_buffer_difference: false
      marker: "👀 "
      type: {
        layout: columnar
        columns: 1
        col_width: 20
        col_padding: 2
      }
      style: {
        text: green
        selected_text: green_reverse
        description_text: yellow
      }
      source: { |buffer, position|
        scope aliases
        | where name == $buffer
        | each { |elt| {value: $elt.expansion }}
      }
    }

4. case-insensitive `where` with `ls`

People often forget that the =~ and !~ are regular expression operators, which means you can do a case-insensitive search like this.

❯ ls | where name =~ '(?i)car'
╭─#─┬────name────┬─type─┬───size───┬────modified────╮
│ 0 │ Cargo.lock │ file │ 160.6 KB │ 8 hours ago    │
│ 1 │ Cargo.toml │ file │   6.4 KB │ 8 hours ago    │
│ 2 │ car.txt    │ file │      0 B │ 11 seconds ago │
╰───┴────────────┴──────┴──────────┴────────────────╯

5. the magic of nushell datatype closures

In your config.nu file you can have themes that color nushell datatypes a particular color. One thing that is sometimes overlooked is that these colors can also be closures, like the one below for string.

string: {|| if $in =~ '^#[a-fA-F\d]+' { $in } else { 'default' } }

This allows nushell to detect anything that looks like a hex color and display that color in nushell.

This allows you to take a file like the x11 rgb.txt file and parse it into colors.

rgb.txt

❯ open ~/Downloads/rgb.txt | lines | last 10
╭───┬───────────────────────────────────╮
│ 0 │ 139   0   0        DarkRed        │
│ 1 │ 144 238 144        light green    │
│ 2 │ 144 238 144        LightGreen     │
│ 3 │ 220  20  60        crimson        │
│ 4 │  75   0 130        indigo         │
│ 5 │ 128 128   0        olive          │
│ 6 │ 102  51 153        rebecca purple │
│ 7 │ 102  51 153        RebeccaPurple  │
│ 8 │ 192 192 192        silver         │
│ 9 │   0 128 128        teal           │
╰───┴───────────────────────────────────╯

And after parsing the file looks similar to this. rgb