SecureCRT is an SSH client software that has both terminal emulator and file transfer functions. It is much more convenient than the ftp command, and the server does not need to open the FTP service. rz, sz are command line tools for ZModem file transfer between Linux/Unix and Windows.
The windows side needs to support ZModem's telnet/ssh client, and SecureCRT can be used to log in to the Unix/Linux host (telnet or ssh can be used).
To upload files, just enter the command "rz" in the shell terminal emulator, select the file on the local disk from the pop-up dialog box, and upload it to the server using Zmodem. To download a file, you only need to enter the command "sz file name" in the shell terminal emulator, and you can use Zmodem to download the file to the "pathSecureCRT-5.1.3download" directory. The default paths for uploading and downloading can be modified through "File Transfer".
If you want to change the background color and file name color of the SecureCRT terminal, just click "Options" - "Session Options" on the menu bar, and select "ANSI Color" and "ANSI Color" in the right window of the "Terminal" - "Simulation" category. Choose an alternative keyboard emulation - Linux".
The XMODEM protocol is an asynchronous file transport protocol widely used in personal computer communications using dial-up modems. This protocol transmits data in 128-byte blocks, and each block uses a checksum process for error detection. If the receiver's checksum for a block is the same as its checksum on the sender, the receiver sends an acknowledge byte to the sender. However, this strategy of acknowledging every block will lead to poor performance, especially in the case of satellite connections with long propagation delays.
A protocol corresponding to XMODEM that uses cyclic redundancy check is called XMODEM-CRC. There is also XMODEM-1K, which transmits data in 1024-byte blocks. ZMODEM is the most efficient version of XMODEM that does not require approval of each block. In fact, it simply requires a retransmission of the corrupted block. ZMODEM is very useful for packet-switched networks that charge per block. Not requiring acknowledgment of loopback packets reduces traffic volume to a great extent.
YMODEM is also an implementation of XMODEM. It includes all the features of XMODEM-1K, plus adds a batch file transfer mode for sending a set of files during a single session.
Zmodem protocol is an enhanced form of Xmodem file transfer protocol. It can not only transfer larger data, but also have a smaller error rate. Contains a feature called checkpoint restart, which allows the transmission to be resumed from the breakpoint rather than from the beginning if the communication link is interrupted during data transfer.
PS: On Linux, the two small tools rz/sz can be installed with lrzsz-xxxx.rpm. Unix can be compiled from the source code. For Solaris spac, you can download the executable code from sunfreeware.