Linux Makefile - Adding a help screen

By using a makefile, you know it already, you can gather in one place a lot of actions like make bash, make build, make deploy, ... just like I do when working on this blog (see my makefile on https://github.com/cavo789/blog/blob/main/makefile).

What's really nice is being able to type make at the command line without any other options and then get a screen with lists of existing commands and a short one-line explanation.

That's what we'll be looking at in this article.

Prerequisites - Install GNU Make if needed

We will use GNU make so you need to have it.

Please run which make in your Linux console to check if make is already installed. If so, you will get f.i. /usr/bin/make as result.

If you got make not found, please run sudo apt-get update && sudo apt-get -y install make to install it.

Prerequisites - Create a sample file

For the demo, please start a Linux shell and run mkdir -p /tmp/makefile && cd $_ to create a folder called makefile in your Linux temporary folder and jump in it.

Please create a new file called makefile with this content:

SHELL:=bash

COLOR_YELLOW:=33

.PHONY: bash
bash:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Start an interactive shell in the Docker container; type exit to quit"

.PHONY: code
code:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Open the blog in Visual Studio Code"

.PHONY: build
build:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Generate a newer version of the build directory"

.PHONY: deploy
deploy: build
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Deploy static pages to the webserver"

.PHONY: install
install:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Generate a newer version of the build directory"

.PHONY: start
start:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Open the blog (http://localhost:3000)"

.PHONY: watch
watch:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Run Docusaurus watcher and open the blog on the localhost. When done, just start a browser and surf to http://localhost:3000"

The indentation in a makefile SHOULD BE made using tabs and not spaces, this is crucial. So please make sure, if your file didn't work, you know what to do.

That file contains a few targets (=actions) and a simple printf statement to display a text. Except echoing something into the console that makefile does nothing.

❯ ls -alh

total 920K
drwxr-xr-x  2 christophe christophe 4.0K Dec  10 12:19 .
drwxrwxrwt 17 root       root       908K Dec  10 12:19 ..
-rw-r--r--  1 christophe christophe 1.4K Dec  10 12:19 makefile

Adding the default action

We're ready to start our implementation.

We have to do three things for this:

Add a default: help action
Add a help: target (a target is, in the Make terminology an action)
Edit each target and add a small description.

Step 1 - Adding the default action

In the absence of a default: action defined in the file, like in your example, the first action will be executed.

So, right now, if you run make (without any other arguments), you'll get the Start an interactive shell... message, that's the result of the bash: target; the first in the file

❯ make

Start an interactive shell in the Docker container; type exit to quit

Please edit the file and add the highlighted line below:

SHELL:=bash

// highlight-next-line
default: help

COLOR_YELLOW:=33

.PHONY: bash
bash:
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Start an interactive shell in the Docker container; type exit to quit"

Step 2 - Adding the help target

Still in your editor, please add the highlighted block below; the position where you'll copy/paste it is not important but, logically, let's put this new action as the first since it's the one that will be executed by default.

SHELL:=bash

default: help

COLOR_YELLOW:=33

// highlight-next-line
.PHONY: help
// highlight-next-line
help: ## Show the help with the list of commands
    // highlight-next-line
 @clear
    // highlight-next-line 
 @awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n\n"} /^[a-zA-Z_-]+:.*?##/ { printf "  \033[36m%-20s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[0;33m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
    // highlight-next-line
 @echo ""

Right now, if you type make on your console, you'll get this:

Usage:
  make <target>

  help                  Show the help with the list of commands

Step 3 - Add a description for each target

Take a look on your new help target: the description Show the help with the list of commands is prefixed by a double #. This is how to add a description.

// highlight-next-line
help: ## Show the help with the list of commands

So, you've to edit your makefile for the last time, and, for each target, add a ## a small, one line, description text; like below, our final file:

SHELL:=bash

COLOR_YELLOW:=33

.PHONY: help
help: ## Show the help with the list of commands
 @clear
 @awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n\n"} /^[a-zA-Z_-]+:.*?##/ { printf "  \033[36m%-20s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[0;33m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 @echo ""

.PHONY: bash
bash: ## Open an interactive shell in the Docker container
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Start an interactive shell in the Docker container; type exit to quit"

.PHONY: code
code: ## Open Visual Studio Code
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Open the blog in Visual Studio Code"

.PHONY: build
build: ## Generate a newer version of the build directory
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Generate a newer version of the build directory"

.PHONY: deploy
deploy: build ## Deploy static pages to the webserver
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Deploy static pages to the webserver"

.PHONY: install
install: ## The very first time, after having cloned this blog, you need to install Docusaurus before using it.
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Generate a newer version of the build directory"

.PHONY: start
start: ## Start the local webserver and open the webpage
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Open the blog (http://localhost:3000)"

.PHONY: watch
watch: ## Start the Docusaurus watcher. Listen any changes to a .md file and reflect the change onto the website
 @printf "\e[1;${COLOR_YELLOW}m%s\e[0m\n\n" "Run Docusaurus watcher and open the blog on the localhost. When done, just start a browser and surf to http://localhost:3000"

And now, by running make you'll get a nice help screen:

Usage:
  make <target>

  help                  Show the help with the list of commands
  bash                  Open an interactive shell in the Docker container
  code                  Open Visual Studio Code
  build                 Generate a newer version of the build directory
  deploy                Deploy static pages to the webserver
  install               The very first time, after having cloned this blog, you need to install Docusaurus before using it.
  start                 Start the local webserver and open the webpage
  watch                 Start the Docusaurus watcher. Listen any changes to a .md file and reflect the change onto the website

As you can see, the order of targets respect the order in your file. help is displayed first because it's the first target in the file so, think to reorder targets in your file based on your logic (f.i. alphabetically).

Step 4 - Add a subtitle between each "main section"

Imagine you have dozens of shares... It would be nice to group them into sections: everything concerning your application, everything relating to your database, actions of the Code Analysis type, and so on.

To do this, simply add a line with this syntax: ##@ My project as illustrated below:

SHELL:=bash

COLOR_YELLOW:=33

.PHONY: help
help: ## Show the help with the list of commands
 @clear
 @awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n\n"} /^[a-zA-Z_-]+:.*?##/ { printf "  \033[36m%-20s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[0;33m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 @echo ""

// highlight-next-line
##@ My project              Helpers to work with the application

.PHONY: bash
bash: ## Open an interactive shell in the Docker container
    # [...]

// highlight-next-line
##@ Data quality            Code analysis tools

.PHONY: phan
phan: ## Run phan analysis
    # [...]

.PHONY: php-cs-fixer
php-cs-fixer: ## Run php-cs-fixer
    # [...]

// highlight-next-line
##@ Database management     Working with the database

.PHONY: phpmyadmin
phpmyadmin: ## Run phpmyadmin web interface
    # [...]

And here is the final result:

Usage:
  make <target>

  help                  Show the help with the list of commands

My project              Helpers to work with the application
  bash                  Open an interactive shell in the Docker container

Data quality            Code analysis tools
  phan                  Run phan analysis
  php-cs-fixer          Run php-cs-fixer

Database management     Working with the database
  phpmyadmin            Run phpmyadmin web interface

Now we have a clear grouping of actions. Much better.