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Exposing Bash Script Functions and calling them in a Makefile Target

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Today I wrote bash file with a bunch of functions in that I wanted to use in a makefile. I did this to automate a manual process I had to test some code.

Exposing these bash functions ended up being trivial as described in this question.

All you have to do is add "[email protected]" as the last line of your bash script.

The answer to this question has the following example script file called test.sh:

testA() {
  echo "TEST A $1";
}

testB() {
  echo "TEST B $2";
}

"[email protected]"

Assuming these are in a file called test.sh we can run the above as follows:

./test.sh testA
>> TEST A
./test.sh testA arg1 arg2
>> TEST A arg1
./test.sh testB arg1 arg2
TEST B arg2

As per this question's answer, this script can be further enhanced by adding a helpful message if the function provided does not exist:

testA() {
  echo "TEST A $1";
}

testB() {
  echo "TEST B $2";
}

if declare -f "$1" > /dev/null
then
  # call arguments verbatim
  "[email protected]"
else
  # Show a helpful error
  echo "'$1' is not a known function name" >&2
  exit 1
fi

Using this in a makefile is actually really easy:

test-a-no-params:
    cd scripts && ./test.sh testA
test-a-with-params:
    cd scripts && ./test.sh testA arg1 arg2
test-b-with-params:
    cd scripts && ./test.sh testB arg1 arg2