slick - async ZSH prompt

How to use

Install:

cargo install slick

To install cargo:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

If in Linux you may need install this:

apt install -y build-essential libssl-dev pkg-config

check your PATH $HOME/.cargo/bin/slick

Quick Test (Development)

For quick testing or development:

# Build and test
cargo build --release
source load.zsh

The load.zsh script automatically detects the slick binary and sets up the prompt.

Production Setup

Add this to your .zshrc:

# Load required modules
zmodload zsh/datetime
autoload -Uz add-zsh-hook

# Register hooks
add-zsh-hook precmd slick_prompt_precmd
add-zsh-hook preexec slick_prompt_preexec

# Register zle widgets
zle -N zle-keymap-select
zle -N zle-line-init

# Global variables
typeset -g slick_prompt_data
typeset -g slick_prompt_timestamp
typeset -g slick_prompt_elapsed

SLICK_PATH=$HOME/.cargo/bin/slick

function slick_prompt_refresh {
    local exit_status=$?
    local line

    # Read ONE line per callback (non-blocking!)
    # ZSH will call this function again if there's more data
    if read -r -u $1 line; then
        slick_prompt_data="$line"

        # Always pass elapsed time if available (needed for ALL phases to show consistent elapsed time!)
        # Use the pre-calculated elapsed time from precmd to avoid flickering
        if [[ -n "$slick_prompt_elapsed" ]]; then
            PROMPT=$($SLICK_PATH prompt -k "$KEYMAP" -r $exit_status -d ${slick_prompt_data:-""} -e $slick_prompt_elapsed)
        else
            PROMPT=$($SLICK_PATH prompt -k "$KEYMAP" -r $exit_status -d ${slick_prompt_data:-""})
        fi

        zle reset-prompt
        return  # RETURN immediately - don't block! Handler will be called again for next line
    fi

    # No more data - close fd and remove handler
    # Clean up timestamp and elapsed now that all phases are complete
    unset slick_prompt_timestamp
    unset slick_prompt_elapsed
    zle -F $1
    exec {1}<&-
}

function zle-line-init zle-keymap-select {
    PROMPT=$($SLICK_PATH prompt -k "$KEYMAP" -d ${slick_prompt_data:-""})
    zle && zle reset-prompt
}

function slick_prompt_precmd() {
    slick_prompt_data=""

    # Calculate elapsed time ONCE here (avoids flickering across multiple render phases)
    # If timestamp is set (command was run), calculate elapsed seconds
    # Otherwise, leave it unset (no command was run, e.g., just pressed enter)
    if [[ -n "$slick_prompt_timestamp" ]]; then
        slick_prompt_elapsed=$(( $EPOCHSECONDS - $slick_prompt_timestamp ))
    else
        unset slick_prompt_elapsed
    fi

    local fd
    exec {fd}< <($SLICK_PATH precmd)
    zle -F $fd slick_prompt_refresh
}

function slick_prompt_preexec() {
    slick_prompt_timestamp=$EPOCHSECONDS

    # Set cursor style
    # 0  ⇒  blinking block.
    # 1  ⇒  blinking block (default).
    # 2  ⇒  steady block.
    # 3  ⇒  blinking underline.
    # 4  ⇒  steady underline.
    # 5  ⇒  blinking bar, xterm.
    # 6  ⇒  steady bar, xterm.

    echo -ne "\e[4 q"
}

🔤 Font Setup

Seeing boxes (□) instead of symbols? You need a Nerd Font.

Quick fix:

1. Download a Nerd Font: https://www.nerdfonts.com/font-downloads
   • Recommended: Monoid Nerd Font (clean, minimalist), JetBrainsMono Nerd Font, FiraCode Nerd Font
2. Install the font on your system
3. Configure your terminal to use it
4. Restart terminal

Using Monoid Nerd Font? Works great with slick's minimalist design!

Don't want to install fonts? Use Unicode or ASCII alternatives:

export SLICK_PROMPT_SYMBOL="→"    # Unicode arrow
# or
export SLICK_PROMPT_SYMBOL=">"    # ASCII

Customizations

Slick can be customized using environment variables.

Quick Start

# Disable git fetch for faster prompts (removes ~500ms auth check on first run)
export SLICK_PROMPT_GIT_FETCH=0

# Custom symbols
export SLICK_PROMPT_SYMBOL="❯"
export SLICK_PROMPT_VICMD_SYMBOL="❮"

# Custom colors
export SLICK_PROMPT_PATH_COLOR=blue
export SLICK_PROMPT_SYMBOL_COLOR=magenta

All Environment Variables

General Settings

export SLICK_PROMPT_CMD_MAX_EXEC_TIME=5        # Max command time to display (seconds)
export SLICK_PROMPT_GIT_FETCH=1                # Enable git fetch (1=yes, 0=no)
export SLICK_PROMPT_NO_GIT_UNAME=0             # Hide git username (1=hide, 0=show)
export SLICK_PROMPT_NON_BREAKING_SPACE=" "     # Non-breaking space character

Prompt Symbols

export SLICK_PROMPT_SYMBOL="$"                 # Main prompt symbol
export SLICK_PROMPT_VICMD_SYMBOL=">"           # Vi command mode symbol
export SLICK_PROMPT_ROOT_SYMBOL="#"            # Root user symbol
export SLICK_PROMPT_GIT_REMOTE_AHEAD="⇡"       # Git ahead symbol
export SLICK_PROMPT_GIT_REMOTE_BEHIND="⇣"      # Git behind symbol
export SLICK_PROMPT_GIT_AUTH_SYMBOL="🔒"       # Git auth failed symbol

Colors

# Colors can be named (red, blue, etc.) or numbers (0-255)
export SLICK_PROMPT_ERROR_COLOR=196            # Error message color
export SLICK_PROMPT_PATH_COLOR=74              # Directory path color
export SLICK_PROMPT_SYMBOL_COLOR=5             # Prompt symbol color
export SLICK_PROMPT_VICMD_COLOR=3              # Vi command mode color
export SLICK_PROMPT_ROOT_COLOR=1               # Root user color
export SLICK_PROMPT_SSH_COLOR=8                # SSH session color
export SLICK_PROMPT_TIME_ELAPSED_COLOR=3       # Command time color

Git Colors

export SLICK_PROMPT_GIT_BRANCH_COLOR=3         # Branch name color
export SLICK_PROMPT_GIT_MASTER_BRANCH_COLOR=160  # master/main branch color
export SLICK_PROMPT_GIT_ACTION_COLOR=3         # Git action (merge, rebase) color
export SLICK_PROMPT_GIT_STATUS_COLOR=5         # Modified files color
export SLICK_PROMPT_GIT_STAGED_COLOR=7         # Staged files color
export SLICK_PROMPT_GIT_REMOTE_COLOR=6         # Remote status color
export SLICK_PROMPT_GIT_UNAME_COLOR=8          # Git username color
export SLICK_PROMPT_GIT_AUTH_COLOR=red         # Git auth failed color

Example Configurations

Minimal/Fast (no network calls)

export SLICK_PROMPT_GIT_FETCH=0           # No git fetch
export SLICK_PROMPT_NO_GIT_UNAME=1        # Hide username
export SLICK_PROMPT_SYMBOL=">"            # Simple symbol

Colorful

export SLICK_PROMPT_SYMBOL="➜"
export SLICK_PROMPT_SYMBOL_COLOR=cyan
export SLICK_PROMPT_PATH_COLOR=blue
export SLICK_PROMPT_GIT_BRANCH_COLOR=yellow
export SLICK_PROMPT_ERROR_COLOR=red

Nerd Fonts (Monoid, JetBrainsMono, etc.)

⚠️ Requires a Nerd Font - Works great with Monoid Nerd Font, JetBrainsMono Nerd Font, FiraCode Nerd Font

# Example with Monoid Nerd Font or similar Nerd Fonts
export SLICK_PROMPT_SYMBOL=""           # nf-oct-chevron_right
export SLICK_PROMPT_VICMD_SYMBOL=""       # nf-oct-chevron_left
export SLICK_PROMPT_ROOT_SYMBOL=""        # nf-fa-flash
export SLICK_PROMPT_GIT_AUTH_SYMBOL=""    # nf-fa-lock
export SLICK_PROMPT_GIT_REMOTE_AHEAD=""   # nf-md-arrow_up
export SLICK_PROMPT_GIT_REMOTE_BEHIND=""  # nf-md-arrow_down

Download Nerd Fonts: https://www.nerdfonts.com/

These symbols work with any Nerd Font (Monoid, JetBrainsMono, FiraCode, Hack, etc.)

See more examples in envrc.

🔒 SSH Authentication Detection

Slick automatically detects when SSH remotes require authentication and displays a lock symbol (🔒).

How it works (Streaming Async Prompts):

• Instant display: Prompt shows immediately with cached auth status (from previous runs)
• Async update: If git fetch is enabled, auth check runs in background with 500ms grace period
• Smart cache: First run takes ~500ms to write cache, subsequent runs are instant with cached status
• Cache-based: Auth status is cached for 5 minutes in ~/.cache/slick/
• Non-blocking: Uses tokio for true async I/O - no delays, no hanging
• Smart timeout: Git fetch has 5-second timeout to prevent indefinite waits

Example:

# cd into repo with SSH remote requiring auth
cd my-private-repo
# First time: ~500ms to check and write cache (shows auth_failed status)
# Subsequent prompts: instant 🔒 from cache (valid for 5 minutes)
# After cache expires (5 min): another ~500ms check to refresh cache

Two-phase rendering:

1. Phase 1 (0ms): Display prompt immediately with all git info + cached auth status
2. Phase 2 (async): Git status updates (~10-50ms), then git fetch checks auth (~500ms)
3. Cache write: Auth status written to cache for next prompt

Configure the lock symbol:

export SLICK_PROMPT_GIT_AUTH_SYMBOL="🔒"  # Default
export SLICK_PROMPT_GIT_AUTH_COLOR=red     # Default

See TEST_README.md for testing instructions.

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Inspired by:

• pure
• purs
• zsh-efgit-prompt