Several UNIX utilities are especially useful for users computing in a
networked, distributed environment. Additional tools for System
Administrators are available but not discussed here.
- The finger command displays information about users on a given host.
The host can be either local or remote.
- Example 1: Show who is logged onto the system
finger - show all local logins
finger @wave.com - show remote system's logins
Login Name TTY Idle When Site Info
rjw Robert J West p0 7:11 Sat 10:32
mdine Marc Dine p1 7:11 Wed 09:46
zepht James S. Tallis p2 7:11 Wed 09:46
bqs5 Barbara Baker p3 8:42 Sat 10:33
davek Dave Kiley p4 8:42 Sat 10:33
- Example 2: Show information about a specific user
finger ksmith - look for a local user
finger dale@wave.com - look for a remote user
Login name: dale In real life: Dale Smith
Directory: /u/ibm/dale Shell: /bin/csh
Project:
Parallel Programming for the masses. (Masses of what!)
Plan:
Think globally, act locally: install solar panels !
- If you create a .plan and/or .project file in your home directory and
make them world readable, they will appear in the Plan and Project
fields of the finger output.
- Finger may be disabled on other
systems for security reasons.
- See the finger man page for details.
- The ping command sends an echo request to a network host. It is useful
for:
- Determining the status of the network and various foreign hosts.
- Tracking and isolating hardware and software problems.
- Testing, measuring, and managing networks.
- The ping command sends one datagram per second and prints one
line of output for every response received. Round-trip times and packet
loss statistics are calculated and displayed.
- Example:
% ping kanaha
PING kanaha.mhpcc.edu: (164.122.27.33): 56 data bytes
64 bytes from 164.122.27.33: icmp_seq=0 ttl=254 time=3 ms
64 bytes from 164.122.27.33: icmp_seq=1 ttl=254 time=2 ms
64 bytes from 164.122.27.33: icmp_seq=2 ttl=254 time=2 ms
64 bytes from 164.122.27.33: icmp_seq=3 ttl=254 time=2 ms
64 bytes from 164.122.27.33: icmp_seq=4 ttl=254 time=2 ms
64 bytes from 164.122.27.33: icmp_seq=5 ttl=254 time=2 ms
^C
----kanaha.mhpcc.edu PING Statistics----
6 packets transmitted, 6 packets received, 0% packet loss
round-trip min/avg/max = 2/2/3 ms
- See the ping man page for details.
- The traceroute command prints the route that IP packets take to a
network host. It is intended for use in network testing, measurement,
and management.
- Example:
% traceroute archie.rutgers.edu
traceroute to dorm.Rutgers.EDU (128.6.18.15), 30 hops max, 40 byte packets
1 B2_IGSL_01 (129.24.96.1) 2 ms 2 ms 2 ms
2 FZ00_rtr_01 (129.24.56.1) 3 ms 2 ms 7 ms
3 msh (129.24.8.193) 5 ms 7 ms 4 ms
4 198.83.5.5 (198.83.5.5) 7 ms 4 ms 7 ms
5 hssi3-0.cnss116.Albuquerque.t3.ans.net (192.103.74.41) 5 ms 4 ms 6 ms
6 mf-0.cnss112.Albuquerque.t3.ans.net (140.222.112.222) 4 ms 4 ms 4 ms
7 t3-0.cnss64.Houston.t3.ans.net (140.222.64.1) 30 ms 30 ms 30 ms
8 t3-0.cnss80.St-Louis.t3.ans.net (140.222.80.1) 47 ms 47 ms 46 ms
9 t3-1.cnss25.Chicago.t3.ans.net (140.222.25.2) 54 ms 52 ms 53 ms
10 t3-0.cnss40.Cleveland.t3.ans.net (140.222.40.1) 60 ms 59 ms 59 ms
11 t3-1.cnss48.Hartford.t3.ans.net (140.222.48.2) 73 ms 78 ms 74 ms
12 t3-2.cnss32.New-York.t3.ans.net (140.222.32.3) 78 ms 76 ms 76 ms
13 t3-0.enss137.t3.ans.net (140.222.137.1) 79 ms 80 ms 86 ms
14 fenchurch-gateway.jvnc.net (192.12.211.65) 83 ms 80 ms 84 ms
15 airport2-gateway.jvnc.net (130.94.9.250) 84 ms 86 ms 88 ms
16 airport1-gateway.jvnc.net (130.94.7.1) 85 ms 92 ms 84 ms
17 rutgers-gateway.jvnc.net (130.94.7.10) 89 ms 86 ms 90 ms
18 rucs-gw.rutgers.edu (128.6.21.7) 94 ms 104 ms 95 ms
19 dorm.rutgers.edu (128.6.18.15) 92 ms 93 ms 91 ms
- Warning: Because of the load traceroute imposes on the network, the
traceroute command should not be used during normal operations or from
automated scripts.
- The traceroute utility may not be available on all systems.
- See the traceroute man page for details.
- Telnet is a utility that allows a computer user at one site to make
a connection, login and then conduct work on
a computer at another site. For example, you can use the telnet
command to run a program in your directory on a supercomputer
thousands of miles away.
- Telnet is used to access many of the Internet resources, such as
databases, libraries and computers
- Example telnet session:
% telnet makena
Trying...
Connected to makena.mhpcc.edu.
Escape character is '^]'.
AIX Version 3
(C) Copyrights by IBM and by others 1982, 1993.
login: jsmith
jsmith's Password:
*********************************************************************
* *
* *
* WELCOME TO THE MAUI HIGH PERFORMANCE COMPUTING CENTER *
* *
* *
*********************************************************************
Last unsuccessful login: Fri Mar 3 12:01:09 HST 1995 on pts/0 from kanaha.mhpcc.edu
Last login: Wed Mar 8 18:33:27 HST 1995 on pts/10
{ do some work }
makena% logout
Connection closed.
- See the telnet man page for details.
- Begin the telnet exercise.
- rlogin (remote login), rsh (remote shell) and rcp (remote copy) are
three utilities which allow you to perform tasks on other machines
without requiring the usual login authentication.
- All three utilities depend upon a .rhosts located in your
home directory. The .rhosts file contains the names of your "trusted"
hosts and your userid on each of those hosts. An example appears below:
apache.unm.edu jsmith
zeus.mit.edu jsmith
athena.com smith
fox.eeco.org smithj
- rlogin: Allows you to login to a remote machine. It is nearly
identical to telnet in function and appearance, however if your .rhosts
file is setup accordingly, you will be able to login to
your account on another machine wihout having to enter a userid and
password.
- rsh: The remote shell command can be used to execute a command on remote
host or log into remote host. With the proper .rhosts file,
authentication is not required.
- Examples:
rsh host2 - will connect to host2 for
login
rsh host2 df - check the amount of free
disk space on remote host2
rsh host2 ps aux |grep jsmith - check for processes owned
by jsmith on host2
rsh host2 rm /tmp/myfile.old - remove a file in host2
rsh host2 cat test1 ">>" test2 - append test1 file on remote
host to test2 file on remote
host
rsh host2 cat test1 >> test2 - append test1 file on remote
host to test2 file on local
host
- rcp: Remote copy enables you to copy files between different systems.
With the proper .rhosts file, authentication is not required.
- Example:
rcp localfile host2:/home/eng/journal
- See the following man pages for details:
- Begin the rlogin, rcp and
rsh exercises.
This concludes the tutorial. Return to the
Table of Contents
