Add exec, upgrade, and mount commands to devc CLI

- exec: Run arbitrary commands in the container
- upgrade: Update Claude Code to latest version
- mount: Add bind mounts to devcontainer.json (recreates container)

Also preserves custom mounts when template command overwrites
existing devcontainer configuration.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: dguido

install.sh

@@ -34,6 +34,9 @@ Commands:
     self-install        Install 'devc' command to ~/.local/bin
     update              Update devc to the latest version
     template [dir]      Copy devcontainer template to directory (default: current)
+    exec [--] <cmd>     Execute a command in the running container
+    upgrade             Upgrade Claude Code to latest version
+    mount <host> <cont> Add a mount to the devcontainer (recreates container)
     help                Show this help message
 
 Examples:
@@ -43,6 +46,9 @@ Examples:
     devc shell                  # Open interactive shell
     devc self-install           # Install devc to PATH
     devc update                 # Update to latest version
+    devc exec -- ls -la         # Run command in container
+    devc upgrade                # Upgrade Claude Code to latest
+    devc mount ~/data /data     # Add mount to container
 EOF
 }
 
@@ -74,6 +80,125 @@ get_workspace_folder() {
   echo "${1:-$(pwd)}"
 }
 
+# Extract custom mounts from devcontainer.json to a temp file
+# Returns the temp file path, or empty string if no custom mounts
+extract_mounts_to_file() {
+  local devcontainer_json="$1"
+  local temp_file
+
+  [[ -f "$devcontainer_json" ]] || return 0
+
+  temp_file=$(mktemp)
+
+  python3 - "$devcontainer_json" "$temp_file" <<'PYTHON'
+import json
+import sys
+
+devcontainer_json = sys.argv[1]
+temp_file = sys.argv[2]
+
+# Default mounts from the template (these should not be preserved as "custom")
+DEFAULT_MOUNT_PREFIXES = [
+    "source=claude-code-bashhistory-",
+    "source=claude-code-config-",
+    "source=claude-code-gh-",
+    "source=${localEnv:HOME}/.gitconfig,",
+]
+
+with open(devcontainer_json) as f:
+    config = json.load(f)
+
+mounts = config.get("mounts", [])
+custom_mounts = []
+
+for mount in mounts:
+    is_default = any(mount.startswith(prefix) for prefix in DEFAULT_MOUNT_PREFIXES)
+    if not is_default:
+        custom_mounts.append(mount)
+
+if custom_mounts:
+    with open(temp_file, "w") as f:
+        json.dump(custom_mounts, f)
+    print(temp_file)
+else:
+    print("")
+PYTHON
+}
+
+# Merge preserved mounts back into devcontainer.json
+merge_mounts_from_file() {
+  local devcontainer_json="$1"
+  local mounts_file="$2"
+
+  [[ -f "$mounts_file" ]] || return 0
+  [[ -s "$mounts_file" ]] || return 0
+
+  python3 - "$devcontainer_json" "$mounts_file" <<'PYTHON'
+import json
+import sys
+
+devcontainer_json = sys.argv[1]
+mounts_file = sys.argv[2]
+
+with open(devcontainer_json) as f:
+    config = json.load(f)
+
+with open(mounts_file) as f:
+    custom_mounts = json.load(f)
+
+existing_mounts = config.get("mounts", [])
+
+# Add custom mounts that aren't already present
+for mount in custom_mounts:
+    if mount not in existing_mounts:
+        existing_mounts.append(mount)
+
+config["mounts"] = existing_mounts
+
+with open(devcontainer_json, "w") as f:
+    json.dump(config, f, indent=2)
+    f.write("\n")
+PYTHON
+}
+
+# Add or update a mount in devcontainer.json
+update_devcontainer_mounts() {
+  local devcontainer_json="$1"
+  local host_path="$2"
+  local container_path="$3"
+  local readonly="${4:-false}"
+
+  python3 - "$devcontainer_json" "$host_path" "$container_path" "$readonly" <<'PYTHON'
+import json
+import sys
+
+devcontainer_json = sys.argv[1]
+host_path = sys.argv[2]
+container_path = sys.argv[3]
+readonly = sys.argv[4] == "true"
+
+with open(devcontainer_json) as f:
+    config = json.load(f)
+
+mounts = config.get("mounts", [])
+
+# Build the new mount string
+mount_str = f"source={host_path},target={container_path},type=bind"
+if readonly:
+    mount_str += ",readonly"
+
+# Remove any existing mount with the same target
+mounts = [m for m in mounts if f"target={container_path}," not in m and not m.endswith(f"target={container_path}")]
+
+mounts.append(mount_str)
+config["mounts"] = mounts
+
+with open(devcontainer_json, "w") as f:
+    json.dump(config, f, indent=2)
+    f.write("\n")
+PYTHON
+}
+
 cmd_template() {
   local target_dir="${1:-.}"
   target_dir="$(cd "$target_dir" 2>/dev/null && pwd)" || {
@@ -82,6 +207,8 @@ cmd_template() {
   }
 
   local devcontainer_dir="$target_dir/.devcontainer"
+  local devcontainer_json="$devcontainer_dir/devcontainer.json"
+  local preserved_mounts=""
 
   if [[ -d "$devcontainer_dir" ]]; then
     log_warn "Devcontainer already exists at $devcontainer_dir"
@@ -91,6 +218,12 @@ cmd_template() {
       log_info "Aborted."
       exit 0
     fi
+
+    # Preserve custom mounts before overwriting
+    preserved_mounts=$(extract_mounts_to_file "$devcontainer_json")
+    if [[ -n "$preserved_mounts" ]]; then
+      log_info "Preserving custom mounts..."
+    fi
   fi
 
   mkdir -p "$devcontainer_dir"
@@ -101,6 +234,13 @@ cmd_template() {
   cp "$SCRIPT_DIR/post_install.py" "$devcontainer_dir/"
   cp "$SCRIPT_DIR/.zshrc" "$devcontainer_dir/"
 
+  # Restore preserved mounts
+  if [[ -n "$preserved_mounts" ]]; then
+    merge_mounts_from_file "$devcontainer_json" "$preserved_mounts"
+    rm -f "$preserved_mounts"
+    log_info "Custom mounts restored"
+  fi
+
   log_success "Template installed to $devcontainer_dir"
 }
 
@@ -155,6 +295,65 @@ cmd_shell() {
   devcontainer exec --workspace-folder "$workspace_folder" zsh
 }
 
+cmd_exec() {
+  local workspace_folder
+  workspace_folder="$(get_workspace_folder)"
+
+  check_devcontainer_cli
+  devcontainer exec --workspace-folder "$workspace_folder" "$@"
+}
+
+cmd_upgrade() {
+  local workspace_folder
+  workspace_folder="$(get_workspace_folder)"
+
+  check_devcontainer_cli
+  log_info "Upgrading Claude Code..."
+
+  devcontainer exec --workspace-folder "$workspace_folder" \
+    npm install -g @anthropic-ai/claude-code@latest
+
+  log_success "Claude Code upgraded"
+}
+
+cmd_mount() {
+  local host_path="${1:-}"
+  local container_path="${2:-}"
+  local readonly="false"
+
+  if [[ -z "$host_path" ]] || [[ -z "$container_path" ]]; then
+    log_error "Usage: devc mount <host_path> <container_path> [--readonly]"
+    exit 1
+  fi
+
+  [[ "${3:-}" == "--readonly" ]] && readonly="true"
+
+  # Expand and validate host path
+  host_path="$(cd "$host_path" 2>/dev/null && pwd)" || {
+    log_error "Host path does not exist: $1"
+    exit 1
+  }
+
+  local workspace_folder
+  workspace_folder="$(get_workspace_folder)"
+  local devcontainer_json="$workspace_folder/.devcontainer/devcontainer.json"
+
+  if [[ ! -f "$devcontainer_json" ]]; then
+    log_error "No devcontainer.json found. Run 'devc template' first."
+    exit 1
+  fi
+
+  check_devcontainer_cli
+
+  log_info "Adding mount: $host_path → $container_path"
+  update_devcontainer_mounts "$devcontainer_json" "$host_path" "$container_path" "$readonly"
+
+  log_info "Recreating container with new mount..."
+  devcontainer up --workspace-folder "$workspace_folder" --remove-existing-container
+
+  log_success "Mount added: $host_path → $container_path"
+}
+
 cmd_self_install() {
   local install_dir="$HOME/.local/bin"
   local install_path="$install_dir/devc"
@@ -232,6 +431,16 @@ main() {
   shell)
     cmd_shell
     ;;
+  exec)
+    [[ "${1:-}" == "--" ]] && shift
+    cmd_exec "$@"
+    ;;
+  upgrade)
+    cmd_upgrade
+    ;;
+  mount)
+    cmd_mount "$@"
+    ;;
   self-install)
     cmd_self_install
     ;;