Using variables in command substitution

["Dan Luther" <dan@xxxxxxxxxxxxxx>]

Hello, 

 

I'm hoping someone can explain this. 

 

I'm trying to unify my .zshrc across a couple of platforms, and I ran across
an interesting ZSH behavior. Essentially, I want to assign a variable to the
name of a specific command for later substitution:

 

  if [$(uname)="SunOS"]; then

    ME="/usr/xpg4/bin/id -un"

  elif [$(uname)="Linux"]; then

    ME="id -un"

  else
    ME="who am i | cut -d ' ' -f1"

  fi

 

  HNAME=$(uname -n | cut -d. -f1)

. . .

 

cd() { chdir "$@"; prompt="[$($ME)@$HNAME] $(pwd)> "; }

 

 . . . 

 

 

When I try to use the "cd" redefinition, I get: 

 

.zshrc: no such file or directory /usr/xpg4/bin/id -un

 

Is it possible to use variables in command expansion at all, or am I just
doing it wrong?

 

Thank you for your time.