variable export in shell

MarioT · 05-15-2006, 06:24 AM

If I open a shell, then it's subshell. In subshell I define variable. How can I export this variable to bi visible in parent shell.
export command export variable only to subshells but not to parent shell.
Define it as system variable doesn't work for me.

Thanks.

Mario

jim mcnamara · 05-15-2006, 06:38 AM

Write the value to a file, and have the parent read the file and export the value.

Have the child kill off the parent.

-- There is a very good reason why this works the way it does. You could not have
two children doing different jobs, then exiting. What the parent would then have in environment variables would be unpredictable. Unpredictable=chaos in computing.

marozsas · 05-15-2006, 07:37 AM

In scripts, you can source the sub-shell. All variables defined in the sub-shell will be visible in the parent.

/tmp/parent.sh

Code:

#!/bin/bash


. /tmp/subshell.sh
echo $MYVAR

/tmp/subshell.sh

Code:

#!/bin/bash

echo $MYVAR
MYVAR=othervalue

execution output

Code:

bash-3.1$ /tmp/parent.sh

othervalue
bash-3.1$

chrism01 · 05-16-2006, 11:52 PM

Note that if you source the shell script, it becomes part of the parent, so no sub-shell is involved(!)