#############    Foregrounding a script    ##############

Ali@DELMAR ~
$ ./monitor.pl

[1]+  Stopped                 ./monitor.pl

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:32:35
Loop #2 at 19:32:36
Loop #3 at 19:32:37

Ali@DELMAR ~
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1856       1    1856       1856  con 1000 18:48:21 /usr/bin/rxvt
     2648    1856    2648       3232    0 1000 18:48:21 /usr/bin/bash
S    3092    2648    3092       3592    0 1000 19:32:35 /usr/bin/perl
     2604    2648    2604        360    0 1000 19:32:44 /usr/bin/ps

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:32:35
Loop #2 at 19:32:36
Loop #3 at 19:32:37

Ali@DELMAR ~
$ fg
./monitor.pl

Ali@DELMAR ~
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1856       1    1856       1856  con 1000 18:48:21 /usr/bin/rxvt
     2648    1856    2648       3232    0 1000 18:48:21 /usr/bin/bash
     3092    2648    3092       3592    0 1000 19:32:35 /usr/bin/perl
      584    2648     584       1992    0 1000 19:33:02 /usr/bin/ps

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:32:35
Loop #2 at 19:32:36
Loop #3 at 19:32:37
Loop #4 at 19:33:1
Loop #5 at 19:33:2
Loop #6 at 19:33:3
Loop #7 at 19:33:4
Loop #8 at 19:33:5
Loop #9 at 19:33:6
Loop #10 at 19:33:7
Loop #11 at 19:33:8
Loop #12 at 19:33:9

Ali@DELMAR ~
$ kill %1
bash: kill: %1: no such job

Ali@DELMAR ~
$ jobs

Ali@DELMAR ~
$ kill 3092

Ali@DELMAR ~
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1856       1    1856       1856  con 1000 18:48:21 /usr/bin/rxvt
     2648    1856    2648       3232    0 1000 18:48:21 /usr/bin/bash
     2284    2648    2284       2368    0 1000 19:33:26 /usr/bin/ps


######################################################################

###########  Backgrounding a script ##############


Ali@DELMAR ~
$ ./monitor.pl

[1]+  Stopped                 ./monitor.pl

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:18:9
Loop #2 at 19:18:11
Loop #3 at 19:18:12
Loop #4 at 19:18:13

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:18:9
Loop #2 at 19:18:11
Loop #3 at 19:18:12
Loop #4 at 19:18:13

Ali@DELMAR ~
$ bg
[1]+ ./monitor.pl &

Ali@DELMAR ~
$

Ali@DELMAR ~
$

Ali@DELMAR ~
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1856       1    1856       1856  con 1000 18:48:21 /usr/bin/rxvt
     2648    1856    2648       3232    0 1000 18:48:21 /usr/bin/bash
     2248    2648    2248       2964    0 1000 19:18:09 /usr/bin/perl
     1992    2648    1992       3624    0 1000 19:18:25 /usr/bin/ps
[1]+  Unknown status          (core dumped) ./monitor.pl

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:18:9
Loop #2 at 19:18:11
Loop #3 at 19:18:12
Loop #4 at 19:18:13
Loop #5 at 19:18:23
Loop #6 at 19:18:24
Loop #7 at 19:18:25
Loop #8 at 19:18:26
Loop #9 at 19:18:27
Loop #10 at 19:18:28

Ali@DELMAR ~
$ cat monitor.out
Loop #1 at 19:18:9
Loop #2 at 19:18:11
Loop #3 at 19:18:12
Loop #4 at 19:18:13
Loop #5 at 19:18:23
Loop #6 at 19:18:24
Loop #7 at 19:18:25
Loop #8 at 19:18:26
Loop #9 at 19:18:27
Loop #10 at 19:18:28
Loop #11 at 19:18:29
Loop #12 at 19:18:30

Ali@DELMAR ~
$ kill %1
bash: kill: %1: no such job

Ali@DELMAR ~
$ kill 2248

Ali@DELMAR ~
$ ps
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1856       1    1856       1856  con 1000 18:48:21 /usr/bin/rxvt
     2648    1856    2648       3232    0 1000 18:48:21 /usr/bin/bash
     2180    2648    2180       1564    0 1000 19:30:21 /usr/bin/ps


######################################################################

###########  The script I used ##############

Ali@DELMAR ~
$ cat monitor.pl 
#!/usr/bin/perl

$outfile = "monitor.out";

open OUTFILE,">$outfile" or die "Can't open output file!";
select(OUTFILE);
$|=1;
$i=0;

while(1) {
    $i++;
    @curtime=localtime;
    print OUTFILE "Loop #$i at $curtime[2]:$curtime[1]:$curtime[0]\n";

    sleep 1;
}

close OUTFILE;