Setting a variable in make

Question

This is my makefile

file1:
    uglifyjs myfile1.js -c | gzip -c -9 > myfile1.min.js

file2:
    uglifyjs myfile2.js -c | gzip -c -9 > myfile2.min.js

How can I change my makefile to remove duplicate code:

file1:
    FILE=myfile1.js
    #How to call build target?

file2:
    FILE=myfile2.js

build:
    uglifyjs $(FILE).js -c | gzip -c -9 > $(FILE).min.js

I know I can use make build but is there another way to do this without invoking make recursively?

MadScientist · Accepted Answer · 2013-07-25 22:39:57Z

1

Use automatic variables:

file1 file2:
        uglifyjs [email protected] -c | gzip -c -9 > [email protected]

I don't know why you're using targets like file1 when the file you're actually building is myfile1.min.js. That's not a good makefile.

But, that's not the question you asked.

answered Jul 25, 2013 at 22:39

MadScientist

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2 Comments

Alan Over a year ago

since my file goes from myfile.js to myfile.min.js, how should I name the target? myfile? Obviously this is an example, but I would prefer to be as idiomatic as possible.

MadScientist Over a year ago

Your target should always be the file that you're creating. If it's not, then every time you run make it will rebuild the file (because as far as it's concerned the file it wants to build, which doesn't exist, is out of date). If you just want the commands to always run you might as well just write a little shell script containing your commands, and not worry about using make.

Chris Dodd · Accepted Answer · 2013-07-25 22:54:49Z

1

Use a pattern rule to run the command, and then make your targets depend on the files you want:

file1: myfile1.min.js
file2: myfile2.min.js

%.min.js: %.js
        uglifyjs $< -c | gzip -c -9 >$@

The pattern rule tells make how to build a .min.js file from a .js file, and the other rules tell it to build specific files.

answered Jul 25, 2013 at 22:54

Chris Dodd

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