Why Emacs project C-c p is undefined?

Question

I am new to Emacs. I have installed Projectile.

When I do C-c p, it says:

C-c p is undefined

Wondering what is wrong?

Following is my ~/.emacs file.

(require 'package)

(add-to-list 'package-archives
                      '("melpa" . "http://melpa.milkbox.net/packages/") t)
(package-initialize)

(defvar required-packages
  '(
    projectile
    ) "a list of packages to ensure are installed at launch.")

(require 'cl)

                    ; method to check if all packages are installed
(defun packages-installed-p ()
  (loop for p in required-packages
    when (not (package-installed-p p)) do (return nil)
    finally (return t)))

                    ; if not all packages are installed, check one by one and install the missing ones.
(unless (packages-installed-p)
                    ; check for new packages (package versions)
  (message "%s" "Emacs is now refreshing its package database...")
  (package-refresh-contents)
  (message "%s" " done.")
                    ; install the missing packages
  (dolist (p required-packages)
    (when (not (package-installed-p p))
      (package-install p))))

(require 'projectile)
(projectile-global-mode)

Edit

My .projectile file

-/venv
-*.pyc
-*.pyc~
-.git
-.gitignore
-.DS_Store

Edit 2

C-h v output for projectile-keymap-prefix as below:

projectile-keymap-prefix is a variable defined in `projectile.el'.
Its value is "^Cp"

Documentation:
Projectile keymap prefix.

You can customize this variable

Edit 3

I am using OS X 10.10.4. I start emacs from command line $emacs. I have installed Emacs using following commands:

brew install emacs --with-cocoa 

And, very first time (when I launch emacs). If do M-x, I don't get project-switch-project, rather I get project-switch-to-buffer. After switching buffer, I can switch project.

Answer 1

You now need to explicitly enable it and set a prefix. The steps to enable Projectile with a C-c C-p prefix:

(projectile-mode +1)
(define-key projectile-mode-map (kbd "C-c C-p") 'projectile-command-map)

This has changed a couple times in 2018. Boris used to set C-c p as the default leader, then changed it to C-c C-p to be in accordance with the emacs keybinding conventions (bullet #2 mentions it.). But now it's removed altogether, so you should set it yourself.

Answer 2

You need to manually activate projectile mode in your ~/.emacs file:

(projectile-mode 1)