Question

I’m trying to create a script that launches another script and have it as a child directly. My goals are:

• the child program should see a different $HOME
• the child script should run in a different directory than the current working directory (i.e. different pwd)
• no extra shells

I achieved the first two goals via subshells and exec, but I’ve yet to manage the third one. Could someone help me?

Here are the details. For ease of description, I will call the first script run, and the other program sleepcmd. Here’s the content of sleepcmd script

echo $HOME && exec sleep 1000

Here’s the content of run script

(HOME=~/foo/bar && cd $HOME/bin && ./sleepcmd)

Adding an exec before ./sleepcmd invocation, i.e.

(HOME=~/foo/bar && cd $HOME/bin && exec ./sleepcmd)

gets this to just one extra shell, compared with running sleepcmd (or sleep) directly.

How can I do better than that, and get rid of the () subshell, while still invoking sleep 1000 with a different $HOME and working directory?

Answer 1

try

pushd
VAR=value command [args...]
popd

e.g.

pushd ~/foo/bar/bin
HOME=~/foo/bar ./sleepcmd
popd