unix - Bad use of parentheses -

i've been stuck on hours:

cd /dir1 (cd $home); pwd; 

why pwd still /dir1 , didn't go home directory?

parentheses start subshell: shell calls fork, , commands inside parentheses executed in subprocess. parent process waits subprocess exit resumes execution. what's happening is:

• execution of cd /dir1: shell performs chdir("/dir1").
• execution of parentheses: shell calls fork, parent process waits child exit.
• execution of cd $home: subshell performs chdir("/home/jurgen").
• the subshell has run out of commands, exits.
• the subshell has exited, wait call in parent returns.
• execution of pwd: shell prints current directory, /dir1.