if you want a copy of this lesson.
"Technology ... the knack of so arranging the world that we need not experience it." -- Max Frisch, Homo Faber
Yesterday I told you that the basic steps in an FTP session are:
1. Start-up your FTP client
2. Give your FTP client an address to connect to (and, just
like TELNET, step one and two can be combined into one
easy step).
3. Identify yourself to the remote site
4. Give the remote site your password
5. Look around the directory for files
6. Change Directories
7. Set the transfer mode (optional)
8. Get the file(s) you want
9. Quit>
I've accessed SURAnet's FTP site (ftp.sura.net), told the site that I am "anonymous", and given the site my full Internet address as my password.
Now that I'm in, I'm going to look around and see what the SURAnet FTP site has to offer.
On most FTP clients, the command to list the contents of the current directory on the remote machine is just
dir
(BTW, you can see a list of all of the acceptable commands for your FTP client by typing "help")
My FTP client accepts and uses the "dir" command, so I type
dir
and the following appears on my screen:
>>>PORT 130,160,4,100,212,230
200 PORT command successful
>>>LIST
150 Opening ASCII mode data connection for /bin/ls.
total 728
drwxrwx--x 3 0 0 512 Aug 5 01:55 bin
drwxr-xr-x 2 0 1 512 May 10 12:47 etc
drwxrwxrwx 6 0 10 512 Oct 21 11:37 incoming
drwxr-xr-x 2 0 0 8192 Feb 15 1992 lost+found
-rw-r--r-- 1 0 1 350142 Oct 25 00:00 ls-lR
drwxrwxr-r 24 0 100 512 May 3 13:25 pub
This is a listing of all of the stuff in the current directory. Let's take a look at the first entry and see if we can figure out what all of this means:
drwxrwx--x 3 0 0 512 Aug 5 01:55 bin
If the line begins with a "-" instead of a "d", it is a file. The letter "d" at the beginning of this example tells me that this is not a file -- it is a subdirectory.
What does THAT mean? Well, pretend that the FTP site is simply a big house. You walk into the house through the front door, and you find yourself standing in an entry hall. The entry hall may have some neat stuff in it, but it also has doors leading to other rooms throughout the house.
The subdirectories -- the "d"s -- are just doors to other "rooms" at the FTP site, and the files -- the "-"s -- are the neat stuff that you can get while you are at the site.
Getting back to our example
drwxrwx--x 3 0 0 512 Aug 5 01:55 bin
the "drwxrwx--x" tells us that this entry is a subdirectory (the "rwxrwx--x" part is just some security stuff). The "512" tells us the size of the subdirectory in bytes. The "Aug 5 01:55" tells us the date and time that this subdirectory was last updated. The last part -- the "bin" -- tells us the name of the subdirectory.
Let's look at one more example:
-rw-r--r-- 1 0 1 350142 Oct 25 00:00 ls-lR
There is a "-" instead of a "d", so this is a file. The "350142" tells us that the size of this file is 350,142 bytes, the file was last updated at midnight on October 25, and the name of this file is "ls-lR".
Finally, let's get back to the main SURAnet directory contents:
drwxrwx--x 3 0 0 512 Aug 5 01:55 bin
drwxr-xr-x 2 0 1 512 May 10 12:47 etc
drwxrwxrwx 6 0 10 512 Oct 21 11:37 incoming
drwxr-xr-x 2 0 0 8192 Feb 15 1992 lost+found
-rw-r--r-- 1 0 1 350142 Oct 25 00:00 ls-lR
drwxrwxr-r 24 0 100 512 May 3 13:25 pub
I want to leave this main directory and get into a subdirectory. To change directories on most FTP clients, you use the command
cd and replace Since I am interested in public information, I'm going to get
into "pub" directory ("pub" is the standard FTP abbreviation
for "public"). I type
cd PUB
and the following appears on my screen:
>>>CWD PUB Uhhh ... what happened?
One of the unfortunate shortcomings of FTP is that, for most of you,
FTP is case sensitive . My "cd PUB" command did not work because
there is no "PUB" directory ... but there IS a "pub" directory :)
Let's try it again. I type
cd pub
and the following appears on my screen:
>>>CWD pub Cool! It worked!
Now I need to see the contents of this new directory that I just
entered. Do you remember what FTP command I should use? (Hint: it is
"dir")
I type "dir", and the following appears on my screen:
>>>PORT 130,160,4,100,215,140 Whoa! That first file -- README -- looks pretty important. I bet
it contains some important information that will make my life a
whole bunch easier (Good rule of thumb: if you see a file that
contains the words README or INDEX, it is an important file).
I need to get this README file.
To get a file using FTP, you use the
get [filename]
command, replaing [filename] with the name of the file that you
want to get. The get command retrieves the file from the remote
site and stores the file on your service provider's system.
Since I want to get the README file, I type
get README
(making sure to use the correct case), and the following appears
on my screen:
Invalid local filename; use 'name.type.mode' or 'name.type'
Now what?!?
This is a problem that some of you may have when you try to get
"one word" files. Some local Internet service providers require
files stored on their machines to have some sort of extension or
type. Your can't have a file whose name is just README ... it
has to be README.[type] (ie. README.DOC, README.TXT, etc).
Since the "get README" command did not work, I'm going to have to
use the
get [filename] [name I want it saved as]
command, replacing [remote file name] with README, and replacing
[name I want it saved as] with the name that I want the file to
be saved as on my service provider's computer.
So, I type
get README README.DOC
and the following appears on my screen:
>>>PORT 130,160,4,100,218,90 After a few additional seconds, the following is added to my screen:
226 Transfer complete.
YIPEE! It worked!! Let's quit FTP and take a look at the file that
I just got.
To quit ftp, you need to use either the "bye" or "quit" commands.
On my client, the command is "quit", so I type
quit
and the following appears on my screen:
221 Goodbye. Okay .. I got the file. But where is it? It is sitting on my
account on my service provider's system!
Depending on your system, it is either easy or hard to get into
the files that get from FTP (in Unix, type "ls"; in VM, type "fl").
Your local Internet service provider can tell you a little more
about how to access, read, and print these files.
Looking at this new file that I just got from FTP, I discover that
the contents of the README file are a brief explanation of what is
in every subdirectory off of the pub directory (cool!):
The following items are available anonymous ftp from
ftp.sura.net:
Directories found under pub:
archie/ Information on the archie service as well as client
software to use archie.
articles/ Text versions of articles in the SURAnet newsletter.
books/ Subdirectory containing information on ordering
discounted books through SURAnet.
databases/ The databases in raw format that are also offered
through our WAIS server.
fdic/ The Federal Deposit Insurance Corporation's ftp
archive.
... [stuff deleted by me]
NEAT! :)
I want to go back and get one of the articles in the SURAnet newsletter.
Thanks to what I learned from the README file, I now know that the
files that I am looking for are in "pub" directory and in the
"articles" subdirectory.
In FTP notation, I can write this as
/pub/articles
This means the same thing as saying "in the pub directory, in
the articles subdirectory" and, as you will soon see, this notation
will eventually even save me a few steps.
Let's go back to SURAnet and get some newsletter articles!
I type
ftp ftp.sura.net
and the following appears on my screen:
Connecting to ftp.sura.net 128.167.254.179, port 21 Since I do not have an account on the SURAnet machine, I type
anonymous
and the following appears on my screen:
>>>USER anonymous I type my full Internet address -- pcrispe1@ua1vm.ua.edu -- as
my password, and the following appears on my screen:
>>>PASS I know that I want to get into the pub directory, and then into
the articles subdirectory. I could type "cd pub" and then "cd articles"
to get into the subdirectory that I want, but it would be easier to
just jump into the "articles" subdirectory with one simple command.
I can make such a jump using the /pub/articles notation introduced a
few minutes ago. If I type
cd /pub/articles
I jump straight into the "articles" directory, and the following appears
on my screen:
>>>CWD /pub/articles Since I have no idea what is in the "articles" subdirectory that I
just entered, I type
dir
and the following appears on my screen:
>>>PORT 130,160,4,100,222,127 COOL! These files already have extensions (winter90.issue, etc.), so
getting them is going to be a breeze!
Let's get the Fall '91 issue. Since I want the file "fall91.issue", I type
get fall91.issue
and the following appears on my screen:
>>>PORT 130,160,4,100,224,34
200 PORT command successful
>>>RETR fall91.issue
150 Opening ASCII mode data connection for fall91.issue (46167 bytes).
After a few seconds, the following is added to my screen:
226 Transfer complete.
47151 bytes transferred. Transfer rate 16.58 Kbytes/sec.
IT WORKED!!! YAY!!! :)
I then quit FTP by typing either "bye" or "quit", and I am done!
The file "fall91.issue" is now sitting in my account on my
local Internet service provider's machine!!
TOMORROW:
- ASCII and Binary files
- getting multiple files
- file compression and unpacking
- FTP using nothing but e-mail
Patrick Douglas Crispen The views expressed in this letter do not necessarily represent the views of the University of Alabama - Tuscaloosa.
ROADMAP: COPYRIGHT PATRICK CRISPEN 1994. ALL RIGHTS RESERVED.
THESE LESSONS ARE BROUGHT TO YOU BY:
BeOnTheNet inc.
+ Providers of Practical Internet Solutions
550 PUB: No such file or directory.
250 CWD command successful.
200 PORT command successful.
>>>LIST
150 Opening ASCII mode data connection for /bin/ls.
Total 56
-rw-rw-r-- 1 1023 100 4052 Apr 22 1994 README
drwxrwsr-x 2 1023 100 512 Aug 6 1993 SURAnet
drwxrwxr-x 6 1020 120 512 Mar 3 1992 archie
drwxrwxr-x 2 1034 120 512 Feb 15 1992 articles
drwxrwxr-x 2 1007 110 512 Jun 22 15:40 books
...[stuff deleted by me]
200 PORT command successful.
>>>RETR README
150 Opening ASCII mode data connection for README (4502 bytes).
4637 bytes transferred. Transfer rate 6.14 Kbytes/sec.
Ready; T=0.54/0.96 01:45:53
dns/ Software and documentation to help setup the Domain
Name Server software on Unix machines (BIND)
220 nic.sura.net FTP server (Version wu-2.4(1) Fri May 20 10:20:58
EDT 1994) ready.
USER (identify yourself to the host):
331 Guest login ok, send your complete e-mail address as password.
Password:
230- SURAnet ftp server running wuarchive experimental ftpd
230-
230-Welcome to the SURAnet ftp server. If you have any problems with
230-the server please mail the to systems@sura.net. If you do have problems,
230-please try using a dash (-) as the first character of your password
230- -- this will turn off the continuation messages that may be confusing
230-your ftp client.
...[stuff deleted by me]
230 Guest login ok, access restrictions apply.
Command:
250 CWD command successful.
Command:
200 PORT command successful
>>>LIST
150 Opening ASCII mode data connection for /bin/ls.
Total 382
-rw-rw-r-- 1 0 120 1510 Jan 3 1992 editors.box.text
-rw-rw-r-- 1 0 120 46167 Jan 3 1992 fall91.issue
-rw-rw-r-- 1 0 120 52864 Jan 3 1992 spring91.issue
-rw-rw-r-- 1 0 120 1515 Jan 3 1992 sub.form.txt
-rw-rw-r-- 1 0 120 36418 Jan 3 1992 summer91.issue
-rw-rw-r-- 1 0 120 53606 Jan 3 1992 winter90.issue
226 Transfer complete
pcrispe1@ua1vm.ua.edu
The University of Alabama
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