How to use variables in a command in sed?

Question

I have abc.sh:

exec $ROOT/Subsystem/xyz.sh

On a Unix box, if I print echo $HOME then I get /HOME/COM/FILE

Answer 1

Say:

sed "s|\$ROOT|${HOME}|" abc.sh

Note:

• Use double quotes so that sed would expand variables.
• Use a separator different than / since the replacement contains /
• Escape the $ in the pattern since you don't want to escape it.

EDIT: In order to replace all occurrences of $ROOT, say

sed "s|\$ROOT|${HOME}|g" abc.sh