How can I find out what these files or processes do (linux)

Question

When I go onto a *nix system and look as ps -A or -e or top I get a large number of processes that are running. For example.

init
migration/0
ksoftirqd/0
events/0
khelper
kacpid
kblockd/0
khubd
pdflush
pdflush
kswapd0
aio/0
kseriod
scsi_eh_0
kjournald
udevd
kauditd
kjournald
kjournald
kjournald
kjournald
kjournald
klogd
portmap
rpc.idmapd
sshd
xinetd
gpm
xfs
salinfod
dbus-daemon-1
cups-config-dae
hald
kjournald
agetty
minilogd
kjournald
screen
bash
sshd
bash

Now some i know what their purpose is, but many i cannot even seem to track down on Google, or i just get oblique references to, such as a post from a forum in 1999 complaining about the process.

Other than tracking them down one by one is there somewhere i can go to get a better explanation?

N.B. I am not asking anyone to tell me directly what they are but pointers to where i can get the understanding myself.

Answer 1

Some processes might have an associated manpage (the d at the end of most processes stand for daemon, you can also try the name without the d)

man processname

Answer 2

The stuff in square brackets are kernel threads. For the others, get the full name (try adding www to the command line) and hit Google, or look at /proc/<pid>/exe and use your package manager to figure out which package the executable comes from.