rz/sz Commands
rz/sz are the Linux/Unix command-line file transfer tools built on the ZMODEM protocol — rz receives and sz sends — widely used for file transfer over serial and SSH terminals.
Purpose
They transfer files bidirectionally in a terminal session with no extra configuration, negotiating ZMODEM protocol parameters automatically.
Mechanism
rz listens to terminal input, recognizes the ZMODEM protocol header, and receives files locally; sz sends a local file to the terminal in ZMODEM frame format. Both rely on the terminal's ZMODEM trigger sequence.
Use cases
- File transfer over SSH terminals
- File exchange during serial debugging
- Automated script file exchange