sed -i命令，用于就地编辑，以与GNU sed和BSD/OSX一起使用 [英] sed -i command for in-place editing to work with both GNU sed and BSD/OSX

问题描述

我有一个makefile(在Linux上是为gmake开发的)，试图将其移植到MacOS，但似乎sed不想合作.我要做的是使用GCC自动生成依赖项文件，然后使用sed对其进行一些调整. makefile:

I've got a makefile (developed for gmake on Linux) that I'm attempting to port to MacOS, but it seems like sed doesn't want to cooperate. What I do is use GCC to autogenerate dependency files, and then tweak them a bit using sed. The relevant portion of the makefile:

$(OBJ_DIR)/%.d: $(SRC_DIR)/%.cpp
  $(CPPC) -MM -MD $< -o $@
  sed -i 's|\(.*\)\.o:|$(OBJ_DIR)/\1.o $(OBJ_DIR)/\1.d $(TEST_OBJ_DIR)/\1_utest.o:|' $@

尽管此程序在GNU/Linux下可以正常运行，但是在MacOS上尝试构建时却出现类似以下的错误:

While this runs with no trouble under GNU/Linux, I get errors like the following when attempting to build on MacOS:

sed: 1: "test/obj/equipmentConta ...": undefined label 'est/obj/equipmentContainer_utest.d'
sed: 1: "test/obj/dice_utest.d": undefined label 'est/obj/dice_utest.d'
sed: 1: "test/obj/color-string_u ...": undefined label 'est/obj/color-string_utest.d'

sed似乎正在砍掉一个字符，但我看不到解决方案.

It would seem like sed is chopping off a character, but I can't see the solution.

推荐答案

OS X sed handles the -i argument differently to the Linux version.

您可以通过添加-e来生成可能对两者都起作用"的命令:

You can generate a command that might "work" for both by adding -e in this way:

#      vv
sed -i -e 's|\(.*\)\.o:|$(OBJ_DIR)/\1.o $(OBJ_DIR)/\1.d $(TEST_OBJ_DIR)/\1_utest.o:|' $@

OS X sed -i将-i之后的下一个内容解释为就地编辑的备份副本的文件扩展名. (Linux版本仅在-i和扩展名之间没有空格的情况下执行此操作.)使用此功能的明显副作用是，您将获得以-e作为扩展名的备份文件. .请参阅此问题的其他答案以获取更多详细信息，以及可以使用的更清洁的方法.

OS X sed -i interprets the next thing after the -i as a file extension for a backup copy of the in-place edit. (The Linux version only does this if there is no space between the -i and the extension.) Obviously a side affect of using this is that you will get a backup file with -e as an extension, which you may not want. Please refer to other answers to this question for more details, and cleaner approaches that can be used instead.

您看到的行为是因为OS X sed使用s|||作为扩展名(！)，然后将 next 参数解释为命令-在这种情况下，它以t开头，sed会将其识别为期望目标标签作为参数的分支到标签"命令-因此您会看到错误.

The behaviour you see is because OS X sed consumes the s||| as the extension (!) then interprets the next argument as a command - in this case it begins with t, which sed recognizes as a branch-to-label command expecting the target label as an argument - hence the error you see.

如果创建文件test，则可以重现该错误:

If you create a file test you can reproduce the error:

$ sed -i 's|x|y|' test
sed: 1: "test": undefined label 'est'

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