FTP Application

JavaScript by A. Sadat

File Transfer Protocol

The file transfer protocol (FTP) allows a user on any computer to get files from another computer, or to send files to another computer. Security is handled by requiring the user to specify a user name and password for the other computer. Provisions are made for handling file transfer between machines with different character set, end of line conventions, etc. (See RFC 959 for specifications for FTP). The FTP Protocol defines methods for transferring files from one computer to another over a network. Computer that stores files using this protocol is called an FTP server or FTP site. Anonymous FTP is used by General Public to access files on a FTP server. Anonymous is entered as username and then a password which is usually an e-mail address. Examples of popular FTP Programs are WS_FTP for the Windows Operating System, the shell based Command-Line FTP program for UNIX & Windows. Web Browsers can be utilized to FTP files. First Type in URL (Uniform Resource Locator) and then the contents of FTP server are displayed in the browser like a table of contents with each file represented by icon and text name. The user clicks on a file to download

FTP Commands

open <server name>
connects to a FTP server
The following example uses the ftp command line program. The open command is used to connect to an ftp server called sweb.uke.edu The ftp server responds with logon date and time. The username of sscho2 is entered. The ftp server prompts for the password. Notice how the typed password is not echoed by the ftp program. Finally the ftp server acknowledges that the user's password was accepted and the user was logged in.

C:\>ftp
ftp> open sweb.uky.edu
Connected to sweb.uky.edu.
220 sweb.uky.edu FTP server (Version wu-2.6.2(1) Mon Mar 11 18:29:02 EST 2002) ready.
User (sweb.uky.edu:(none)): sscho2
331 Password required for sscho2.
Password:
230 User sscho2 logged in.
ftp>

get <remote file name> <local file name>
retrieves file from server(download)
The following example transfers the file mytar on the ftp server to the current directory on the client as mytar2. The file is transfered in ASCII mode which is the current default. The ftp server responds with the number of bytes transferred and the time taken

ftp> get mytar mytar2
200 PORT command successful.
150 Opening ASCII mode data connection for mytar (30720 bytes).
226 Transfer complete.
ftp: 30767 bytes received in 1.21Seconds 25.41Kbytes/sec.
ftp>

put <remote file name>> <local file name>
sends file to server(upload)
The following example sets the transfer mode to binary and then sends the gp.pdf in the current directory on the client to the current directory on the server. Since a second arguement was omitted the file has the same name on the server.

ftp> bin
200 Type set to I.
ftp> put gp.pdf
200 PORT command successful.
150 Opening BINARY mode data connection for gp.pdf.
226 Transfer complete.
ftp: 546110 bytes sent in 34.92Seconds 15.64Kbytes/sec.
ftp>

close or disconnect
ends ftp session, close connection to server
Closes the connection, but ftp program on client is still running.

ftp> close
221-You have transferred 0 bytes in 0 files.
221-Total traffic for this session was 222 bytes in 0 transfers.
221-Thank you for using the FTP service on sweb.uky.edu.
221 Goodbye.
ftp>

bye or exit
ends ftp program

ftp> bye
221-You have transferred 1122748 bytes in 3 files.
221-Total traffic for this session was 1124238 bytes in 5 transfers.
221-Thank you for using the FTP service on sweb.uky.edu.
221 Goodbye.

cd <file name>
changes directory on server
This example changes the directory on the ftp server to the www directory in the current directory
ftp> cd www 250 CWD command successful. ftp>

ls
list contents of current directory

ftp> ls
200 PORT command successful.
150 Opening ASCII mode data connection for file list.
form.htm
index.htm
phpform.php
process.php
variables.php
226 Transfer complete.
ftp: 62 bytes received in 0.01Seconds 6.20Kbytes/sec.
ftp>

lcd
local change directory
This example changes the directory to \temp on the client
ftp> lcd \temp Local directory now C:\Temp. ftp>
mkdir <directory name>
creates a directory on server
This example makes a directory called stan in the current directory on the ftp server
ftp> mkdir stan 257 "/u2/sscho2/stan" new directory created. ftp>
pwd
prints name of working directory on server
This example display the current working directory on the server, which is /u2/sscho2
ftp> pwd 257 "/u2/sscho2" is current directory. ftp>
binary (image)
file transferred will be in binary mode
no character conversion
Used to transfer executable file
ftp> binary 200 Type set to I. ftp>
ascii
ASCII is the defaultmethod of character conversion for file transfer. Provides either ascii to EBCDIC or EBCDIC to ascii if the character representation of the sending and receiving operating systems are different.
ftp> ascii 200 Type set to A. ftp>
delete <file name>
removes file from server
This example deletes the file gp.pdf in the current directory on the ftp server.
ftp> delete gp.pdf 250 DELE command successful. ftp>

More Information

FTP RFC

Exercises

The _____________ allows a user on any computer to get files from another computer.
________ FTP is Used by General Public to access files on a FTP server
________ is a popular windows based FTP Program
________ is the FTP command that connects to a FTP server
________ is the FTP command that retrieves file from server(download)
________ is the FTP command that ends an ftp program
________ is the FTP command that states the file transferred will be in binary mode
________ is the FTP command that states the file transferred will be in text mode