Introduction to FTP
FTP is a network protocol used for exchanging files over a TCP/IP network. FTP implements user-based password authentication. FTP also allows anonymous user access, where the password is usually a valid email address. You can access a remote system for exchanging files using the ftp command.
# ftp hostname/IP address
If you do not have the ftp command available on your system, you can install it using the package manager available. For Example, for CentOS/RHEL systems:
# yum install ftp
FTP Commands
Following are some of the frequently used ftp commands:
| Command | Description |
|---|---|
| open | opens a connection with another computer on the network. |
| get | transfers a file from the remote system to the local system’s current directory. |
| put | transfers a file from the local system to a directory on the remote system. |
| mget | transfers multiple files from the remote system to the local system’s current directory. |
| mput | transfers multiple files from the local system to a directory on the remote system. |
| bye/quit | enable exiting the FTP environment. |
| close | Terminates a connection with another computer |
| ascii | Sets the mode of file transfer to ASCII |
| binary | Sets the mode of file transfer to binary |
| cd | Changes directory on the remote machine |
| delete | Deletes or removes a file in the current remote directory |
| help | Requests a list of all available FTP commands |
| lcd | Changes directory on your local machine |
| ls | Lists the names of the files in the current remote directory |
| mkdir | Makes a new directory within the current remote directory |
| pwd | Finds out the path name of the current directory on the remote machine |
| rmdir | Removes or deletes a directory in the current remote directory |
| prompt | Prompts you to confirm the transfer of each file before completing the transfer. By default, prompting is set to on. |
FTP Transfer Modes
FTP supports two types of transfer modes:
- American Standard Code for Information Interchange (ASCII) mode: transfers plain files such as text files.
- Binary mode: Binary mode enables you to transfer binary, image, or any nontext files.
Transferring Files Using ASCII Mode
The example Below we will:
1. establish an FTP connection from the host1 system to the host2 system.
2. After the connection is established, we will change the transfer mode to ASCII mode.
3. The we will get the file test1.txt on host2, store the test1.txt file in local directory on host1, and quit the FTP session.
$ ftp host2 Connected to host2. 220 host2 FP server ready. Name (host2:user): user 331 Password required for user. Password: password 230 User user logged in. Remote system type is UNIX. Using binary mode to transfer files.
ftp> ascii 200 Type set to A.
ftp> ls 200 PORT command successful. 150 Opening ASCII mode data connection for file list. test1.txt (directory list truncated) 226 Transfer complete. 133 bytes received in 0.081 seconds (1.61 Kbytes/s)
ftp> get test1.txt 200 PORT command successful. 150 Opening ASCII mode data connection for test1.txt (57 bytes). 226 Transfer complete. local: test1.txt remote: test1.txt 66 bytes received in 0.042 seconds (1.54 Kbytes/s)
ftp> bye 221-You have transferred 66 bytes in 1 files. 221-Total traffic for this session was 1326 bytes in 4 transfers. 221-Thank you for using the FTP service on host2. 221 Goodbye.
Transferring Files Using Binary Mode
The example Below shows how to transfer a binary file.
$ ftp host2 Connected to host2. 220 host2 FTP server ready. Name (host2:user2): user2 331 Password required for user2. Password: 230 User user2 logged in. Remote system type is UNIX.
ftp> get binary.file 200 PORT command successful. 150 Opening BINARY mode data connection for binary.file (19084 bytes). 226 Transfer complete. local: binary.file remote: binary.file 19084 bytes received in 0.0044 seconds (4212064 Kbytes/s)
Transferring Multiple Files
The example shown below establishes an FTP connection from the host1 system to the host2 system and transfers multiple files by using the prompt, mget, and mput commands.
$ ftp host2 Connected to host2. 220 host2 FTP server ready. Name (host2:user2): user2 331 Password required for user2. Password: 230 User user2 logged in. Remote system type is UNIX. Using binary mode to transfer files.
By default the prompt mode is on, when you type the prompt command, it will disable the prompt mode (interactive mode) and you will not be asked for confirmations before you perform any action like get, put etc.
ftp> prompt Interactive mode off
ftp> mget file.1 file.2 200 PORT command successful. 150 Opening BINARY mode data 226 Transfer complete. 200 PORT command successful. 150 Opening BINARY mode data 226 Transfer complete.
ftp> mput file3 file4 200 PORT command successful. 150 Opening BINARY mode data 226 Transfer complete.