Defining local variable in Makefile target - gnu-make

Question

How to define local variable in Makefile target?
I would like to avoid repeating filename like:
zsh:
FILENAME := "text.txt"
#echo "Copying ${FILENAME}...";
scp "${FILENAME}" "user#host:/home/user/${FILENAME}"
But I am getting an error:
FILENAME := "text.txt"
/bin/sh: FILENAME: command not found
Same with $(FILENAME)
Trying
zsh:
export FILENAME="text.txt"
#echo "Copying ${FILENAME} to $(EC2)";
Gives me an empty value:
Copying ...

Answer 1

You can't define a make variable inside a recipe. Recipes are run in the shell and must use shell syntax.
If you want to define a make variable, define it outside of a recipe, like this:
FILENAME := text.txt
zsh:
#echo "Copying ${FILENAME}...";
scp "${FILENAME}" "user#host:/home/user/${FILENAME}"
Note, it's virtually never correct to add quotes around a value when assigning it to a make variable. Make doesn't care about quotes (in variable values or expansion) and doesn't treat them specially in any way.

Answer 2

The rules for a target are executed by the shell, so you can set a variable using shell syntax:
zsh:
#FILENAME="text.txt"; \
echo "Copying $${FILENAME}..."; \
scp "$${FILENAME}" "user#host:/home/user/$${FILENAME}"
Notice that:
I'm escaping end-of-line using \ so that everything executes in
the same shell
I'm escaping the $ in shell variables by writing $$ (otherwise
make will attempt to interpret them as make variables).
For this rule, which apparently depends on a file named text.txt,
you could alternatively declare text.txt as an explicit dependency and then write:
zsh: text.txt
#echo "Copying $<..."; \
scp "$<" "user#host:/home/user/$<"