The output of ps includes the status:
$ ps aux | head -n2
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 200892 5132 ? Ss Mar04 0:20 /sbin/init
The STAT column is the state of the process. This can be one of (from man ps):
Here are the different values that the s, stat and state output
specifiers (header "STAT" or "S") will display to describe the state of a process:
D uninterruptible sleep (usually IO)
R running or runnable (on run queue)
S interruptible sleep (waiting for an event to complete)
T stopped by job control signal
t stopped by debugger during the tracing
W paging (not valid since the 2.6.xx kernel)
X dead (should never be seen)
Z defunct ("zombie") process, terminated but not reaped by its parent
So, you are looking for processes whose state is shown as T. To see only those processes, you can parse the ps output for them:
ps aux | awk '$8=="T"'
Sometimes, additional characters can be added to the state field (depending on the options you use), so this might be a safer approach:
ps aux | awk '$8~/T/'