May 23, 2021 UNIX Getting started
If the user works in a distributed environment, the user needs to communicate with the remote user, and the user needs to access the UNIX host remotely.
Below are some of the utilities in UNIX operating systems that are dedicated to network communication between users in distributed environments.
The ping instruction sends an answer request to a host on the network. T his instruction is primarily used to detect whether the remote host can communicate properly.
Ping instructions can be used for the following purposes:
Here's the syntax for using the ping instruction:
$ping hostname or ip-address
The above designation continuously prints the response message. The user can press the CTRL - C button at the same time to end the printing of the information.
Here's an example of detecting whether a host in your network is reachable:
$ping google.com
PING google.com (74.125.67.100) 56(84) bytes of data.
64 bytes from 74.125.67.100: icmp_seq=1 ttl=54 time=39.4 ms
64 bytes from 74.125.67.100: icmp_seq=2 ttl=54 time=39.9 ms
64 bytes from 74.125.67.100: icmp_seq=3 ttl=54 time=39.3 ms
64 bytes from 74.125.67.100: icmp_seq=4 ttl=54 time=39.1 ms
64 bytes from 74.125.67.100: icmp_seq=5 ttl=54 time=38.8 ms
--- google.com ping statistics ---
22 packets transmitted, 22 received, 0% packet loss, time 21017ms
rtt min/avg/max/mdev = 38.867/39.334/39.900/0.396 ms
$
If a host is not reachable, the following information is displayed:
$ping giiiiiigle.com
ping: unknown host giiiiigle.com
$
FTP is short for File Transfer Protocol. Use this tool to help users upload or download files between hosts.
The FTP tool has its own UNIX instructions that can do the following:
Here's the syntax for using the ftp instruction:
$ftp hostname or ip-address
The above instructions trigger a login interface that enters the account number and password. If the account number and password entered by the user are authenticed, the user can access the root of the account entered accordingly, and then a variety of actions can be performed.
Here are some common actions:
Instructions | Describe |
---|---|
put filename | Upload files locally to the remote server |
get filename | Download files locally from the remote server |
mput file list | Upload files in bulk from local to remote servers |
mget file list | Download files locally in bulk from the remote server |
prompt off | Close file reminders so that every file is not asked for every time you operate mput and mget. |
prompt on | Turn on file reminders |
dir | Lists all files in the current directory on the remote server |
cd dirname | Switch the directory on the local host to the specified directory |
lcd dirname | Switch the directory on the remote server to the specified directory |
quit | Sign out of the current landing |
It is important to note that the local host directory is the current directory when the files are uploaded and downloaded. I f the user wants to upload or download a file's directory as a specific directory, the user needs to switch the current directory to the specified directory before uploading or downloading.
Here are some examples of ftp operations:
$ftp amrood.com
Connected to amrood.com.
220 amrood.com FTP server (Ver 4.9 Thu Sep 2 20:35:07 CDT 2009)
Name (amrood.com:amrood): amrood
331 Password required for amrood.
Password:
230 User amrood logged in.
ftp> dir
200 PORT command successful.
150 Opening data connection for /bin/ls.
total 1464
drwxr-sr-x 3 amrood group 1024 Mar 11 20:04 Mail
drwxr-sr-x 2 amrood group 1536 Mar 3 18:07 Misc
drwxr-sr-x 5 amrood group512 Dec 7 10:59 OldStuff
drwxr-sr-x 2 amrood group 1024 Mar 11 15:24 bin
drwxr-sr-x 5 amrood group 3072 Mar 13 16:10 mpl
-rw-r--r-- 1 amrood group 209671 Mar 15 10:57 myfile.out
drwxr-sr-x 3 amrood group512 Jan 5 13:32 public
drwxr-sr-x 3 amrood group512 Feb 10 10:17 pvm3
226 Transfer complete.
ftp> cd mpl
250 CWD command successful.
ftp> dir
200 PORT command successful.
150 Opening data connection for /bin/ls.
total 7320
-rw-r--r-- 1 amrood group 1630 Aug 8 1994 dboard.f
-rw-r----- 1 amrood group 4340 Jul 17 1994 vttest.c
-rwxr-xr-x 1 amrood group 525574 Feb 15 11:52 wave_shift
-rw-r--r-- 1 amrood group 1648 Aug 5 1994 wide.list
-rwxr-xr-x 1 amrood group 4019 Feb 14 16:26 fix.c
226 Transfer complete.
ftp> get wave_shift
200 PORT command successful.
150 Opening data connection for wave_shift (525574 bytes).
226 Transfer complete.
528454 bytes received in 1.296 seconds (398.1 Kbytes/s)
ftp> quit
221 Goodbye.
$
Users often experience the need to connect to a remote UNIX host and to operate on a remote host. Telnet is a tool that allows users to connect, log on, and operate remotely on remote servers.
Once a user logs on to a remote server using the Telnet tool, the user can operate the remote server to perform tasks as if it were a local host operation. Here's an example of a Telnet conversation:
C:>telnet amrood.com
Trying...
Connected to amrood.com.
Escape character is '^]'.
login: amrood
amrood's Password:
*****************************************************
* *
* *
*WELCOME TO AMROOD.COM *
* *
* *
*****************************************************
Last unsuccessful login: Fri Mar 3 12:01:09 IST 2009
Last login: Wed Mar 8 18:33:27 IST 2009 on pts/10
{ do your work }
$ logout
Connection closed.
C:>
The finger directive is used to display information about the user on the specified host. T he host here can be between a local host and a remote server.
For security reasons, finger can also be used in other systems.
Here's a simple syntax for using the finger instruction.
An example of detecting information about a densoed user in a local host is as follows:
$ finger
Login Name Tty Idle Login Time Office amrood pts/0 Jun 25 08:03 (62.61.164.115)
Here's an example of getting information about a valid user specified on the local host:
$ finger amrood
Login: amrood Name: (null)
Directory: /home/amrood Shell: /bin/bash
On since Thu Jun 25 08:03 (MST) on pts/0 from 62.61.164.115
No mail.
No Plan.
An example of detecting information about all landing users in a remote server is as follows:
$ finger @avtar.com
Login Name Tty Idle Login Time Office
amrood pts/0 Jun 25 08:03 (62.61.164.115)
Here's an example of getting the specified valid user information on a remote server:
$ finger [email protected]
Login: amrood Name: (null)
Directory: /home/amrood Shell: /bin/bash
On since Thu Jun 25 08:03 (MST) on pts/0 from 62.61.164.115
No mail.
No Plan.