Understanding subshell

To understand concept of subshell, let us take an example


suppose we execute following command

root#pwd

/root

root#cd /opt/backup;pwd

output will be

/opt/backup

root# pwd

/opt/backup

Now try to execute following command

root# (cd /opt/backup;pwd)

/opt/backup

But

root#pwd

/root

We can notice the diffrence , in () causes sub-shell to be invoked, in

which change of directory in executed, after executing pwd in subshell

the sub shell ceases to exist. back in current shell , so we are still

in /root