How to apply an environment variable for the whole command

Question

In my Bash terminal, I regularly execute a chain of commands. For example:

cmd1 && cmd2 && cmd3

Now, I want to define an environment variable which is applied to all three commands and which only scoped to those commands. I tried:

MY_VAR=abc cmd1 && cmd2 && cmd3

But it seems that now only cmd1 sees MY_VAR.

Is there a way to apply the environment variable to all three commands? I know I could export in advance, but I prefer to declare the environment variable locally in an ad-hoc fashion, so it will never impact subsequent commands.

It it matters, I am using urxvt as terminal emulator.

Answer 1

Repeat it: MY_VAR=abc cmd1 && MY_VAR=abc cmd2 && MY_VAR=abc cmd3

Or use a subshell:

   # wrapper subshell for the commands
   cmds () 
   {
      cmd1 && cmd2 && cmd3
   }

   # invoke it
   MY_VAR=abc cmds

If you need to enter the whole thing in one go, do:

   cmds() { cmd1 && cmd2 && cmd3; }; MY_VAR=abc cmds

Answer 2

The way to do it is:

MY_VAR=abc; cmd1 && cmd2 && cmd3

What makes the difference is the colon after the assignment.

Without the colon ;, MY_VAR=abc cmd1 && ... this cause the assignment to be part of the cmd1 element of the conditional expression. Anything at the other side of the logical AND: && can not see the local environment of the other condition elements.