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What is shell in makefile?
$(shell) is a special function in gmake that runs an external command and captures the output for use in the makefile. For example, you could get the current working directory like this: CWD=$(shell pwd) all: @echo This makefile lives in $(CWD).
What is GNU Make file?
GNU Make is a tool which controls the generation of executables and other non-source files of a program from the program’s source files. Make gets its knowledge of how to build your program from a file called the makefile, which lists each of the non-source files and how to compute it from other files.
Which is the standard GNU shell?
While the GNU operating system will most likely include a version of the Berkeley shell csh, Bash will be the default shell. Like other GNU software, Bash is quite portable. The POSIX Shell and Tools standard has been developed by IEEE Working Group 1003.2 (POSIX.
Where does GNU make search for the shell?
In MS-DOS, GNU make searches for the shell in the following places: In the precise place pointed to by the value of SHELL. For example, if the makefile specifies ‘SHELL = /bin/sh’, make will look in the directory /bin on the current drive. In the current directory. In each of the directories in the PATH variable, in order.
Where to find the shell file in makefile?
For example, if the makefile specifies ‘ SHELL = /bin/sh ’, make will look in the directory /bin on the current drive. In the current directory. In each of the directories in the PATH variable, in order. In every directory it examines, make will first look for the specific file ( sh in the example above).
How to write makefiles for a GNU program?
Conventions for writing makefiles for GNU programs. A quick reference for experienced users. A list of common errors generated by make . A real example of a straightforward, but nontrivial, makefile. License for copying this manual.
Which is the program used as the shell?
The program used as the shell is taken from the variable SHELL . If this variable is not set in your makefile, the program /bin/sh is used as the shell. The argument(s) passed to the shell are taken from the variable .SHELLFLAGS. The default value of .SHELLFLAGS is -c normally, or -ec in POSIX-conforming mode.