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<h1 class="subsection">Using Variables in Recipes</h1> <p>The other way in which <code>make</code> processes recipes is by expanding any variable references in them (see <a href="reference">Basics of Variable References</a>). This occurs after make has finished reading all the makefiles and the target is determined to be out of date; so, the recipes for targets which are not rebuilt are never expanded. </p> <p>Variable and function references in recipes have identical syntax and semantics to references elsewhere in the makefile. They also have the same quoting rules: if you want a dollar sign to appear in your recipe, you must double it (‘<samp>$$</samp>’). For shells like the default shell, that use dollar signs to introduce variables, it’s important to keep clear in your mind whether the variable you want to reference is a <code>make</code> variable (use a single dollar sign) or a shell variable (use two dollar signs). For example: </p> <div class="example"> <pre class="example">LIST = one two three
all:
for i in $(LIST); do \
echo $$i; \
done
</pre>
</div> <p>results in the following command being passed to the shell: </p> <div class="example"> <pre class="example">for i in one two three; do \
echo $i; \
done
</pre>
</div> <p>which generates the expected result: </p> <div class="example"> <pre class="example">one
two
three
</pre>
</div><div class="_attribution">
<p class="_attribution-p">
Copyright © 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022 Free Software Foundation, Inc. <br>Licensed under the GNU Free Documentation License.<br>
<a href="https://www.gnu.org/software/make/manual/html_node/Variables-in-Recipes.html" class="_attribution-link">https://www.gnu.org/software/make/manual/html_node/Variables-in-Recipes.html</a>
</p>
</div>
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