ds - Docker Shell Helper

A simple zsh function for easily shelling into running Docker containers with tab completion.

Installation

Add this to your ~/.zshrc:

# Docker shell helper - shell into running containers
ds() {
  local container="${1}"
  local shell_cmd="${2:-}"
  
  if [[ -z "$container" ]]; then
    echo "Usage: ds <container> [shell]"
    echo ""
    echo "Examples:"
    echo "  ds my-container"
    echo "  ds nginx-123 /bin/sh"
    return 1
  fi
  
  # Show which container we're entering
  echo "\033[36m🐳 Entering container:\033[0m \033[1;34m$container\033[0m"
  
  if [[ -n "$shell_cmd" ]]; then
    echo "\033[90m→ Running: $shell_cmd\033[0m"
    docker exec -it "$container" "$shell_cmd"
  else
    if docker exec "$container" command -v /bin/bash &>/dev/null; then
      echo "\033[90m→ Running: /bin/bash\033[0m"
      docker exec -it "$container" /bin/bash
    else
      echo "\033[90m→ Running: /bin/sh\033[0m"
      docker exec -it "$container" /bin/sh
    fi
  fi
}

# Fuzzy completion for ds (inline, no popup)
_ds_complete() {
  if [[ $CURRENT -eq 2 ]]; then
    local containers=($(docker ps --filter "status=running" --format '{{.Names}}' 2>/dev/null))
    local partial="${words[CURRENT]}"
    local matches=()
    
    # Fuzzy matching: find containers that contain the partial string (case insensitive)
    for container in "${containers[@]}"; do
      if [[ -z "$partial" ]] || [[ "${container:l}" == *"${partial:l}"* ]]; then
        matches+=("$container")
      fi
    done
    
    # If no substring matches, try simpler pattern matching
    if [[ ${#matches[@]} -eq 0 && -n "$partial" ]]; then
      for container in "${containers[@]}"; do
        # Simple character sequence check: all chars from partial must appear in order
        local container_lower="${container:l}"
        local remaining="$container_lower"
        local found=1
        
        for (( i=1; i<=${#partial}; i++ )); do
          local char="${partial[i]:l}"
          if [[ "$remaining" == *"$char"* ]]; then
            # Remove everything up to and including this character
            remaining="${remaining#*$char}"
          else
            found=0
            break
          fi
        done
        
        if [[ $found -eq 1 ]]; then
          matches+=("$container")
        fi
      done
    fi
    
    if [[ ${#matches[@]} -gt 0 ]]; then
      _describe 'containers' matches
    fi
  fi
}

compdef _ds_complete ds

Then reload your shell:

source ~/.zshrc

Usage

# Shell into a container (auto-detects bash/sh)
ds my-container

# Use a specific shell
ds nginx-container /bin/zsh

# Fuzzy completion examples:
ds nginx<TAB>  # Shows all containers containing "nginx"
ds dep<TAB>    # Shows deployment-* containers  
ds djg<TAB>    # Shows docker-jenkins-group (character sequence: d-j-g)
ds api<TAB>    # Shows containers containing "api"

Features

• 🚀 Simple zsh function - no external scripts
• 🔍 Fuzzy completion - substring and character sequence matching (case insensitive)
• ⚡ Inline completion - works like standard tab completion but with fuzzy search
• 🎯 No dependencies - pure zsh, no fzf or external tools required
• 🐚 Automatic shell detection (/bin/bash → /bin/sh fallback)
• ⚙️ Override shell with second argument
• 📦 All-in-one - just add to your zshrc

Requirements

• Zsh shell
• Docker installed and accessible
• Running Docker containers (for completion to work)

How It Works

1. Function: Creates a ds function in your shell
2. Fuzzy Completion: Substring matching (case-insensitive) + character sequence matching (e.g., "djg" matches "docker-jenkins-group")
3. Filtering: Only shows running containers (excludes restarting/stopped containers)
4. Shell Detection: Tries /bin/bash first, falls back to /bin/sh
5. Execution: Uses docker exec -it for interactive sessions

That's it! No files to manage, everything in your zshrc. 🎉