fish - Is there a way to prepend a command with a variable assignment like in bash?

Question

In bash one can write

CFLAGS="-O2" rvm install 2.0.0

to run rvm with that specific CFLAGS . Is there anyway to do the same in fish shell?

I know about set -x but that is not exactly the same as the environment variable will be set for the whole session instead of just for that command.

Answer 1

根据 fish FAQ，要么使用：

env CFLAGS="-O2" rvm install 2.0.0

（这不适用于 fish 内置函数或函数，仅适用于外部命令），或

begin
    set -lx CFLAGS="-O2"
    rvm install 2.0.0
end

（这有点笨拙；在GitHub 问题 #438上有改进建议）。

Answer 2

您可以env为此使用命令：

env FOO=BAR command

将运行command环境变量 FOO 设置为 BAR。