Editing Make (software) (section)

==Use==

In general, based on a makefile, Make updates target files from source files if any source file has a newer [[timestamp]] than the target file or the target file does not exist. For example, this could include compiling [[C (programming language)|C]] files ({{Code|*.c}}) into [[object file]]s, then linking the object files into an executable program. Or this could include compiling [[TypeScript]] files ({{Code|*.ts}}) to [[JavaScript]] for use in a browser. Other examples include: convert a source image file to another format, copy a file to a content management system, and send e-mail about build status.

A makefile defines targets where each is either a file to generate or is a user-defined concept, called a ''phony'' target.

Make updates the targets passed as arguments:

<syntaxhighlight lang="bash">
make [-f makefile] [options] [targets]
</syntaxhighlight>

If no target is specified, Make updates the first target in the makefile which is often a phony target to perform the most commonly used action.

Make skips build actions if the target file timestamp is after that of the source files.<ref>[http://alvinalexander.com/linux/unix-linux-ls-command-file-sort-sorting How to sort Linux ls command file output] {{webarchive |url=https://web.archive.org/web/20160913020855/http://alvinalexander.com/linux/unix-linux-ls-command-file-sort-sorting |date=September 13, 2016 }}</ref> Doing so optimizes the build process by skipping actions when the target file is up-to-date, but sometimes updates are skipped erroneously due to file timestamp issues including restoring an older version of a source file, or when a [[Network File System|network filesystem]] is a source of files and its clock or time zone is not synchronized with the machine running Make. Also, if a source file's timestamp is in the future, make repeatedly triggers unnecessary actions, causing longer build time.

When Make starts, it uses the makefile specified on the command-line or if not specified, then uses the one found by via specific search rules. Generally, Make defaults to using the file in the [[working directory]] named {{mono|Makefile}}. GNU Make searches for the first file matching: {{mono|GNUmakefile}}, {{mono|makefile}}, or {{mono|Makefile}}.

Make processes the options of the command-line based on the loaded makefile.