class: center, middle, inverse, title-slide # Introduction to make ### Colin Rundel ### 2018-10-18 --- exclude: true --- class: middle count: false # make --- ## make * Automatically build software / libraries / documents by specifying dependencies via a `Makefile` * Originally created by Stuart Feldman in 1976 at Bell Labs * Almost universally available (all flavors of unix / linux / osx) --- ## Makefile A `Makefile` provides a list of target files along with their dependencies and the steps necessary to generate each of the targets. ``` target1: depend1 depend2 depend3 ... step1 step2 step3 ... depend1: depend1.1 step1 step2 ``` --- ## Makefile (simple example) ```make paper.html: paper.Rmd Fig1/fig.png Fig2/fig.png Rscript -e "library(rmarkdown);render('paper.Rmd')" Fig1/fig.png: Fig1/fig.R cd Fig1;Rscript fig.R Fig2/fig.png: Fig2/fig.R cd Fig2;Rscript fig.R ``` --- ## Smart Building Because the `Makefile` specifies the dependency structure `make` knows when a file has changed (by examining the file's modification timestamp) and only runs the steps that depend on the file(s) that have changed. <br /> * After running `make` the first time, I edit `paper.Rmd`, what steps run if I run `make` again? * What about editing `Fig1/fig.R`? --- ## Variables Like R or other language we can define variables ```make R_OPTS=--no-save --no-restore --no-site-file --no-init-file --no-environ Fig1/fig.png: Fig1/fig.R cd Fig1;Rscript $(R_OPTS) fig.R ``` --- ## Special Targets By default is you run `make` without arguments it will attempt to build the *first* target in the `Makefile` (whose name does not start with a `.`). By convention we often include an `all` target which explicitly specifies how to build everything within the project. <br /> `all` is an example of what is called a phony target - because there is no file named `all` in the directory. Other common phony targets: * clean - remove any files created by the Makefile, restores to the original state * install - for software packages, installs the compiled programs / libraries / headers <br /> We specify phony targets by including a line with `.PHONY` as the target and the phony targets as dependencies, i.e.: ```make .PHONY: all clean all ``` --- ## Builtin Variables * `$@` - the file name of the target * `$<` - the name of the first dependency * `$^` - the names of all dependencies * `$(@D)` - the directory part of the target * `$(@F)` - the file part of the target * `$(<D)` - the directory part of the first dependency * `$(<F)` - the file part of the first dependency --- ## Pattern Rules Often we want to build several files in the same way, in these cases we can use `%` as a special wildcard character to match both targets and dependencies. So we can go from ```make Fig1/fig.png: Fig1/fig.R cd R;Rscript fig.R Figs2/fig.png: Fig1/fig.R cd R;Rscript fig.R ``` to ```make Fig%/fig.png: Fig%/fig.R cd $(<D);Rscript $(<F) ``` --- ## Makefile (fancier example) ```make all: paper.html paper.html: paper.Rmd Fig1/fig.png Fig2/fig.png Rscript -e "library(rmarkdown);render('paper.Rmd')" Fig%/fig.png: Fig%/fig.R cd $(<D);Rscript $(<F) clean: rm -f paper.html rm -f Fig*/*.png .PHONY: all clean ``` --- ## HW5's Makefile <br/> <br/> <br/> <br/> .center[.large[ Live Demo ]] --- ## Acknowledgments Above materials are derived in part from the following sources: * Karl Broman - [minimal make](http://kbroman.org/minimal_make/)