how to set and use multiple parameters in single environmental variable in fish shell

Question

I want to use following in fish shell:

$ export arm='ARCH=arm CROSS_COMPILE=arm-eabi-'
$ make $arm 

This works fine in bash/zsh but not on fish shell.

But if I execute the following in fish shell:

$env tmp=arm make

this works fine.

Can someone please help me with this?

Answer 1

You're looking for set -x:

set -x arm 'ARCH=arm CROSS_COMPILE=arm-eabi-'

See the tutorial section on environment variables for more.

Answer 2

In sh/bash:

export arm='ARCH=arm CROSS_COMPILE=arm-eabi-'
make $arm

Doesn't really make sense. Environment variables are meant as variables passed to make (so a reference to $(arm) in the Makefile for instance expands to its content). Environment variables are scalar, they can contain only one string value. Above you're relying on the split+glob operator of the shell that splits the variable into words passed to make (as arguments).

But $arm is expanded by the shell, so you don't need to export arm to the environment of make because make makes no use of that $arm variable.

Also, on a shell that supports them, it would make more sense to use arrays. In bash /zsh/ksh:

arm=(ARCH=arm CROSS_COMPILE=arm-eabi-)
make "${arm[@]}"

With fish:

set arm ARCH=arm CROSS_COMPILE=arm-eabi-
make $arm

With rc/es/zsh:

arm=(ARCH=arm CROSS_COMPILE=arm-eabi-)
make $arm