Hi. GNU Make uses /bin/sh by default for running recipe lines and $(shell ) functions.
You can change the shell by setting the 'SHELL' variable. One note for this variable is that SHELL is never set from the environment. This is clearly documented [1]. The build system of a large project is often divided into multiple sub-makes. The top Makefile, and several sub-Makefiles. Other variables can be set in the top Makefile, and exported down to sub-makes. For example: export CC := gcc export LD := ld export OBJCOPY := objcopy ... But, since it is not possible to propagate SHELL down to sub-makes, we end up with adding the same setup: SHELL := /bin/bash in every sub-makefiles. So, here is one suggestion. Does it make sense to add an environment variable with a less common name? It functions in the same way as SHELL, but the difference is that it can be set from the environment. For example, 'MAKE_SHELL'. In the top Makefile, you can do: export MAKE_SHELL := /bin/bash then, GNU Make will use /bin/bash not only in the top Makefile but also in sub-makefiles. [1] https://www.gnu.org/software/make/manual/html_node/Choosing-the-Shell.html -- Best Regards Masahiro Yamada
