Various Tools

Zen and the Art of the Internet

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 Various Tools
 
New and interesting ways to use the Internet are being dreamed up
every day.  As they gain wide-spread use, some methods become
near-standard (or actual written standard) tools for Internet users to
take advantage of.  A few are detailed here; there are undoubtedly
others, and new ideas spring up all the time.  An active user of the
Internet will discover most of the more common ones in time.  Usually,
these services are free.  Commercial Services for applications
that are commercially available over the Internet.
 
Usenet is often used to announce a new service or capability on
the Internet.  In particular, the groups comp.archives and
comp.protocols.tcp-ip are good places to look.  Information
will drift into other areas as word spreads.  Usenet News for
information on reading news.
 
Finger
 
On many systems there exists the finger command, which yield
information about each user that's currently logged in.  This command
also has extensions for use over the Internet, as well.  Under normal
circumstances, the command is simply finger for a summary of who's
logged into the local system, or finger username for specific
information about a user. It's also possible to go one step further
and go onto the network.  The general usage is
 
finger @hostname
 
To see who's currently logged in at Widener University, for instance, use
 
% finger @cs.widener.edu
[cs.widener.edu]
Login       Name              TTY Idle    When            Where
brendan  Brendan Kehoe         p0      Fri 02:14  tattoo.cs.widene
sven     Sven Heinicke         p1      Fri 04:16  xyplex3.cs.widen
 
 
To find out about a certain user, they can be fingered specifically
(and need not be logged in):
 
% finger bart@cs.widener.edu
[cs.widener.edu]
Login name: bart                        In real life: Bart Simpson
Directory: /home/springfield/bart       Shell: /bin/underachiever
Affiliation: Brother of Lisa            Home System: channel29.fox.org
Last login Thu May 23 12:14 (EDT) on ttyp6 from channel29.fox.org.
No unread mail
Project: To become a "fluff" cartoon character.
Plan:
Don't have a cow, man.
 
 
Please realize that some sites are very security conscious, and need
to restrict the information about their systems and users available
to the outside world.  To that end, they often block finger requests
from outside sites---so don't be surprised if fingering a computer or
a user returns with Connection refused.
 
Internet Relay Chat
 
The Lamont View Server System
On lamont.ldgo.columbia.edu in pub/gb.tar.Z.
 
Ping
 
The ping command allows the user to check if another system is
currently ``up'' and running.  The general form of the command
is ping system. {The usage will, again, vary.}
For example,
 
ping cs.widener.edu
 
will tell you if the main machine in Widener University's Computer
Science lab is currently online (we certainly hope so!).
 
Many implementations of ping also include an option to let you
see how fast a link is running (to give you some idea of the load on
the network).  For example:
 
% ping -s cs.swarthmore.edu
PING cs.swarthmore.edu: 56 data bytes
64 bytes from 130.58.68.1: icmp_seq=0 ttl=251 time=66 ms
64 bytes from 130.58.68.1: icmp_seq=1 ttl=251 time=45 ms
64 bytes from 130.58.68.1: icmp_seq=2 ttl=251 time=46 ms
^C
--- cs.swarthmore.edu ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max = 45/52/66 ms
 
 
This case tells us that for cs.swarthmore.edu it takes about 46
milliseconds for a packet to go from Widener to Swarthmore College and
back again.  It also gives the average and worst-case speeds, and any
packet loss that may have occurred (e.g. because of network
congestion).
 
While ping generally doesn't hurt network performance, you
shouldn't use it too often---usually once or twice will leave
you relatively sure of the other system's state.
 
Talk
 
Sometimes email is clumsy and difficult to manage when one really
needs to have an interactive conversation.  The Internet provides for
that as well, in the form of talk. Two users can literally see
each other type across thousands of miles.
 
To talk with Bart Simpson at Widener, one would type
 
talk bart@@cs.widener.edu
 
which would cause a message similar to the following to be displayed
on Bart's terminal:
 
Message from Talk_Daemon@cs.widener.edu at 21:45 ...
talk: connection requested by joe@ee.someplace.edu
talk: respond with:  talk joe@ee.someplace.edu
 
Bart would, presumably, respond by typing talk joe@ee.someplace.edu.
They could then chat about whatever they wished, with instantaneous
response time, rather than the write-and-wait style of email.  To
leave talk, on many systems one would type Ctrl-C (hold down
the Control key and press C).  Check local documentation to be sure.
 
There are two different versions of talk in common use today.  The
first, dubbed ``old talk,'' is supported by a set of Unix systems
(most notably, those currently sold by Sun).  The second, ntalk
(aka ``new talk''), is more of the standard.  If, when attempting to
talk with another user, it responds with an error about protocol
families, odds are the incompatibilities between versions of talk is
the culprit.  It's up to the system administrators of sites which use
the old talk to install ntalk for their users.