How to source a script in a Makefile?

问题:

Is there a better way to source a script, which sets env vars, from within a makefile?

FLAG ?= 0
ifeq ($(FLAG),0)
export FLAG=1
/bin/myshell -c '<source scripts here> ; $(MAKE) $@'
else
...targets...
endif

回答1:

To answer the question as asked: you can't.

The basic issue is that a child process can not alter the parent's environment. The shell gets around this by not forking a new process when source'ing, but just running those commands in the current incarnation of the shell. That works fine, but make is not /bin/sh (or whatever shell your script is for) and does not understand that language (aside from the bits they have in common).

Chris Dodd and Foo Bah have addressed one possible workaround, so I'll suggest another (assuming you are running GNU make): post-process the shell script into make compatible text and include the result:

shell-variable-setter.make: shell-varaible-setter.sh
    postprocess.py @^

# ...
else
include shell-variable-setter.make
endif

messy details left as an exercise.

回答2:

Makefile default shell is /bin/sh which does not implement source.

Changing shell to /bin/bash makes it possible:

# Makefile

SHELL := /bin/bash

rule:
    source env.sh && YourCommand

回答3:

If your goal is to merely set environment variables for Make, why not keep it in Makefile syntax and use the include command?

include other_makefile

If you have to invoke the shell script, capture the result in a shell command:

JUST_DO_IT=$(shell source_script)

the shell command should run before the targets. However this won't set the environment variables.

If you want to set environment variables in the build, write a separate shell script that sources your environment variables and calls make. Then, in the makefile, have the targets call the new shell script.

For example, if your original makefile has target a, then you want to do something like this:

# mysetenv.sh
#!/bin/bash
. <script to source>
export FLAG=1
make "$@" 

# Makefile
ifeq($(FLAG),0)
export FLAG=1
a: 
    ./mysetenv.sh a
else
a:
    .. do it
endif

回答4:

Using GNU Make 3.81 I can source a shell script from make using:

rule:
<tab>source source_script.sh && build_files.sh

build_files.sh "gets" the environment variables exported by source_script.sh.

Note that using:

rule:
<tab>source source_script.sh
<tab>build_files.sh

will not work. Each line is ran in its own subshell.

回答5:

This works for me. Substitute env.sh with the name of the file you want to source. It works by sourcing the file in bash and outputting the modified environment, after formatting it, to a file called makeenv which is then sourced by the makefile.

IGNORE := $(shell bash -c "source env.sh; env | sed 's/=/:=/' | sed 's/^/export /' > makeenv")                         
include makeenv   

回答6:

Some constructs are the same in the shell and in GNU Make.

var=1234
text="Some text"

You can alter your shell script to source the defines. They must all be simple name=value types.

Ie,

[script.sh]

. ./vars.sh

[Makefile]

include vars.sh

Then the shell script and the Makefile can share the same 'source' of information. I found this question because I was looking for a manifest of common syntax that can be used in Gnu Make and shell scripts (I don't care which shell).

Edit: Shells and make understand ${var}. This means you can concatenate, etc, var="One string" var=${var} "Second string"

回答7:

I really like Foo Bah's answer where make calls the script, and the script calls back to make. To expand on that answer I did this:

# Makefile
.DEFAULT_GOAL := all 

ifndef SOME_DIR

%:
<tab>. ./setenv.sh $(MAKE) $@

else

all:
<tab>...

clean:
<tab>...

endif

--

# setenv.sh
export SOME_DIR=$PWD/path/to/some/dir

if [ -n "$1" ]; then
    # The first argument is set, call back into make.
    $1 $2
fi

This has the added advantage of using $(MAKE) in case anyone is using a unique make program, and will also handle any rule specified on the command line, without having to duplicate the name of each rule in the case when SOME_DIR is not defined.

回答8:

My solution to this: (assuming you're have bash, the syntax for $@ is different for tcsh for instance)

Have a script sourceThenExec.sh, as such:

#!/bin/bash
source whatever.sh
$@

Then, in your makefile, preface your targets with bash sourceThenExec.sh, for instance:

ExampleTarget:
    bash sourceThenExec.sh gcc ExampleTarget.C

You can of course put something like STE=bash sourceThenExec.sh at the top of your makefile and shorten this:

ExampleTarget:
    $(STE) gcc ExampleTarget.C

All of this works because sourceThenExec.sh opens a subshell, but then the commands are run in the same subshell.

The downside of this method is that the file gets sourced for each target, which may be undesirable.

回答9:

Another possible way would be to create a sh script, for example run.sh, source the required scripts and call make inside the script.

#!/bin/sh
source script1
source script2 and so on

make 

回答10:

If you need only a few known variables exporting in makefile can be an option, here is an example of what I am using.

$ grep ID /etc/os-release 

ID=ubuntu
ID_LIKE=debian


$ cat Makefile

default: help rule/setup/lsb

source?=.

help:
        -${MAKE} --version | head -n1

rule/setup/%:
        echo ID=${@F}

rule/setup/lsb: /etc/os-release
        ${source} $< && export ID && ${MAKE} rule/setup/$${ID}


$ make

make --version | head -n1
GNU Make 3.81
. /etc/os-release && export ID && make rule/setup/${ID}
make[1]: Entering directory `/tmp'
echo ID=ubuntu
ID=ubuntu

-- http://rzr.online.fr/q/gnumake

回答11:

If you want to get the variables into the environment, so that they are passed to child processes, then you can use bash's set -a and set +a. The former means, "When I set a variable, set the corresponding environment variable too." So this works for me:

check:
    bash -c "set -a && source .env.test && set +a && cargo test"

That will pass everything in .env.test on to cargo test as environment variables.

Note that this will let you pass an environment on to sub-commands, but it won't let you set Makefile variables (which are different things anyway). If you need the latter, you should try one of the other suggestions here.

回答12:

Depending on your version of Make and enclosing shell, you can implement a nice solution via eval, cat, and chaining calls with &&:

ENVFILE=envfile

source-via-eval:
  @echo "FOO: $${FOO}"
  @echo "FOO=AMAZING!" > $(ENVFILE)
  @eval `cat $(ENVFILE)` && echo "FOO: $${FOO}"

And a quick test:

> make source-via-eval
FOO:
FOO: AMAZING!

回答13:

target: output_source
    bash ShellScript_name.sh

try this it will work, the script is inside the current directory.