B.1. How can I list all the programs that are running, and kill a troublesome one?

Just as Windows users hit CtrlAlt Del to show the Task Manager, Fedora users can access Applications > System Tools > System Monitor to start the System Monitor. This tool allows you very simply to select a process; hit End Process to kill it.

If you prefer to work from the command line, you can list all the processes running on the machine using the ps command:

[kermit@swinetrek ~]$ ps axu
USER     PID %CPU %MEM   VSZ   RSS TTY   STAT START TIME COMMAND
root       1  0.0  0.4  1744   544 ?     S    Nov01 0:04 init [5]
root       2  0.0  0.0     0     0 ?     SN   Nov01 0:00 [ksofirq]
root       3  0.0  0.0     0     0 ?     S    Nov01 0:00 [watcdog]
root       4  0.0  0.0     0     0 ?     S<   Nov01 0:00 [evens/0]
root       5  0.0  0.0     0     0 ?     S<   Nov01 0:00 [khelper]
…
kermit  2447  0.0  3.4 22196  4300 ?     S    Nov01 0:10 /usr/libe
snort   2516  0.2  9.2 50544 11624 ?     Ss   Nov01 0:48 /usr/sbin
root   28872  0.0  2.2 10864  2868 ?     S    Nov01 0:01 smbd -D
root   29809  0.0  1.7  7248  2260 ?     Ss   Nov01 0:00 sshd: ker
kermit 29812  0.0  1.8  7248  2332 ?     S    Nov01 0:00 sshd: ker
kermit 29813  0.0  1.1  4384  1408 pts/1 Ss   Nov01 0:00 -bash
kermit 30227  0.0  0.7  4488   936 pts/1 R+   00:46 0:00 ps axu
[kermit@swinetrek ~]$ 

To search for a particular process, use grep on the output of ps:

[kermit@swinetrek ~]$ ps axu | grep snort
snort   2516  0.2  9.2  50544 9636 ?     Ss   Nov01 0:48 
    /usr/sbin/snort -A fast -b -d -D -i eth0 -u snort -g snort 
    -c /etc/snort/snort.conf -l /var/log/snort
kermit 30403  0.0  0.3   3732  384 pts/1 R+   01:01 0:00 
    grep snort
[kermit@swinetrek ~]$ 

The second column2516 in the above exampleidentifies the process ID. Kill the process by passing that process ID to the kill command:

[root@swinetrek kermit]# kill 2516
[root@swinetrek kermit]#