GNU make manual 翻译( 一百三十四)

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5.3.1 Using One Shell

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Sometimes you would prefer that all the lines in the recipe be passed

to a single invocation of the shell.  There are generally two

situations where this is useful: first, it can improve performance in

makefiles where recipes consist of many command lines, by avoiding

extra processes.  Second, you might want newlines to be included in

your recipe command (for example perhaps you are using a very different

interpreter as your `SHELL').  If the `.ONESHELL' special target

appears anywhere in the makefile then _all_ recipe lines for each

target will be provided to a single invocation of the shell.  Newlines

between recipe lines will be preserved.  For example:



     .ONESHELL:

     foo : bar/lose

             cd $(@D)

             gobble $(@F) > ../$@



would now work as expected even though the commands are on different

recipe lines.

5.3.1 使用 One Shell
---------------------

有些时候可能想要一个片段的所有行都被传递给shell的一次激活。在两种情况下，这是有用的: 

首先，当片段由很多命令行组成的时候，它能够避免额外的处理以提高性能。

第二，你可能想要在片段中包含新的行 (例如你可能正在使用一个非常不一样的解释器来作为你的shell)。

如果特殊目的 .ONESHELL 出现在makefile的任何地方，每一个目的的所有行都会被一个单独的shell 激活所处理。片段之间的新行被保留。例如:

.ONESHELL:

foo : bar/lose
cd $(@D)
gobble $(@F) > ../$@

将会按照预想的方式来工作，哪怕是他们在不同的行。

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