Question

I have two shell scripts a.sh and b.sh in my home directory. Within a.sh i invoke b.sh as

sh b.sh

I can also do it the following way

. b.sh

Kindly tell me the differences between the invocations.

Thanks,
LinuxPenseur

Answer 1

The first way:

sh b.sh

creates a subshell and runs b.sh within the subshell. One of the consequences of doing it this way is that any environment variables set in b.sh will simply vanish when you return to a.sh

The second method:

. ./b.sh

sources b.sh and therefore any env vars set in b.sh will remain visible to a.sh when b.sh returns.