3

If I append this: 

hi=11
export hi

to the .bashrc and then I su to this user with: 

su - bela

then I: 

echo $hi
11

Then it's working, the "hi" variable has the value of "11". But. When I: 

su -c "echo $hi" bela

the variable "hi" has no value. Why?

(running on CentOS 6)

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1 Answer 1

Reset to default
9

su -c "echo $hi" bela expands to the words su, -c, echo ​ and bela. Since the variable hi is not defined in your current shell, its expansion is empty. The command that is executed as user bela is echo ​.

Fix: su -c 'echo $hi' bela, with the single quotes protecting the $ from expansion… Not. The .bashrc file is only read by interactive shells. When you run su -c 'echo $hi' bela, this executes echo $hi as user bela. But since nothing is defining the variable hi, the command echo $hi expands to echo which still prints nothing.

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2
  • yeah, interesting. i would have expected a non-login shell opened by su to read .bashrc, but it doesn't. moving the definition of $hi to .bash_profile works when used with su -c 'echo $hi' -l bela, though, when the login shell reads .bash_profile.
    – Tim Kennedy
    Commented Nov 17, 2011 at 3:21
  • it works with ' ' :D
    – LanceBaynes
    Commented Nov 18, 2011 at 6:22

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