When a process is running, backgrounded or suspended, it will be entered onto a list along with a job number. To examine this list, type
jobs
An example of a job list could be
[1] Suspended sleep 1000
[2] Running netscape
[3] Running matlab
To restart (foreground) a suspended processes, type
fg %jobnumber
For example, to restart sleep 1000, type
fg %1
Typing fg with no job number foregrounds the last suspended process.