关键词：lrzsz、minicom、ZMODEM、MD5sum等。
在环境受限的嵌入式系统上，往往只有串口可以使用。
此时如果需要传输文件，需要借助rz/sz工具，可以使用的传输协议有ZMODEM、YMODEM、XMODEM，一般首选的是ZMODEM。
这里记录minicom下使用rz/sz进行文件传输的操作。
首先说明一下rz和sz的文件传输方向，这些命令都是在调试板上执行的，调试板通过串口和PC相连。
rz表示调试版发起从PC接收文件，sz表示调试版发送向PC传送文件。
1. 使能sz/rz工具
通过buildroot打开Target packages->Networking applications->lrzsz，也即打开了BR2_PACKAGE_LRZSZ。
2. minicom下使用sz/rz工具
2.1 minicom下sz发送文件
首先看一下sz的使用，最简单的就是“sz filename”，传送的文件默认在启动minicom的路径。
如果想指定路径可以通过“sz -f full_path_name”实现，这种方法会在目标板上同样地址保存文件。这样做需要谨慎。
在文件传输结束后，调试版和PC两边通过md5sum验证一下传输数据有效性。
更多使用方法：
sz version 0.12.20 Usage: sz [options] file ... or: sz [options] -{c|i} COMMAND Send file(s) with ZMODEM/YMODEM/XMODEM protocol (X) = option applies to XMODEM only (Y) = option applies to YMODEM only (Z) = option applies to ZMODEM only -+, --append append to existing destination file (Z) -2, --twostop use 2 stop bits -4, --try-4k go up to 4K blocksize --start-4k start with 4K blocksize (doesn't try 8) -8, --try-8k go up to 8K blocksize --start-8k start with 8K blocksize -a, --ascii ASCII transfer (change CR/LF to LF) -b, --binary binary transfer -B, --bufsize N buffer N bytes (N==auto: buffer whole file) -c, --command COMMAND execute remote command COMMAND (Z) -C, --command-tries N try N times to execute a command (Z) -d, --dot-to-slash change '.' to '/' in pathnames (Y/Z) --delay-startup N sleep N seconds before doing anything -e, --escape escape all control characters (Z) -E, --rename force receiver to rename files it already has -f, --full-path send full pathname (Y/Z) -i, --immediate-command CMD send remote CMD, return immediately (Z) -h, --help print this usage message -k, --1k send 1024 byte packets (X) -L, --packetlen N limit subpacket length to N bytes (Z) -l, --framelen N limit frame length to N bytes (l>=L) (Z) -m, --min-bps N stop transmission if BPS below N -M, --min-bps-time N for at least N seconds (default: 120) -n, --newer send file if source newer (Z) -N, --newer-or-longer send file if source newer or longer (Z) -o, --16-bit-crc use 16 bit CRC instead of 32 bit CRC (Z) -O, --disable-timeouts disable timeout code, wait forever -p, --protect protect existing destination file (Z) -r, --resume resume interrupted file transfer (Z) -R, --restricted restricted, more secure mode -q, --quiet quiet (no progress reports) -s, --stop-at {HH:MM|+N} stop transmission at HH:MM or in N seconds --tcp build a TCP connection to transmit files --tcp-server open socket, wait for connection -u, --unlink unlink file after transmission -U, --unrestrict turn off restricted mode (if allowed to) -v, --verbose be verbose, provide debugging information -w, --windowsize N Window is N bytes (Z) -X, --xmodem use XMODEM protocol -y, --overwrite overwrite existing files -Y, --overwrite-or-skip overwrite existing files, else skip --ymodem use YMODEM protocol -Z, --zmodem use ZMODEM protocol
2.2 minicom下rz接收文件
通过rz接收文件，首先需要输入tz：
然后输入Ctrl+A，紧接着按下Z，在按下S(Send files)。
选择zmodem，进入文件选择界面。
上下键或者PageUp/PageDown移动，空格选择文件。
同样使用md5sum进行验证。
rz version 0.12.20 Usage: rz [options] [filename.if.xmodem] Receive files with ZMODEM/YMODEM/XMODEM protocol (X) = option applies to XMODEM only (Y) = option applies to YMODEM only (Z) = option applies to ZMODEM only -+, --append append to existing files -a, --ascii ASCII transfer (change CR/LF to LF) -b, --binary binary transfer -B, --bufsize N buffer N bytes (N==auto: buffer whole file) -c, --with-crc Use 16 bit CRC (X) -C, --allow-remote-commands allow execution of remote commands (Z) -D, --null write all received data to /dev/null --delay-startup N sleep N seconds before doing anything -e, --escape Escape control characters (Z) -E, --rename rename any files already existing --errors N generate CRC error every N bytes (debugging) -h, --help Help, print this usage message -m, --min-bps N stop transmission if BPS below N -M, --min-bps-time N for at least N seconds (default: 120) -O, --disable-timeouts disable timeout code, wait forever for data --o-sync open output file(s) in synchronous write mode -p, --protect protect existing files -q, --quiet quiet, no progress reports -r, --resume try to resume interrupted file transfer (Z) -R, --restricted restricted, more secure mode -s, --stop-at {HH:MM|+N} stop transmission at HH:MM or in N seconds -S, --timesync request remote time (twice: set local time) --syslog[=off] turn syslog on or off, if possible -t, --timeout N set timeout to N tenths of a second -u, --keep-uppercase keep upper case filenames -U, --unrestrict disable restricted mode (if allowed to) -v, --verbose be verbose, provide debugging information -w, --windowsize N Window is N bytes (Z) -X --xmodem use XMODEM protocol -y, --overwrite Yes, clobber existing file if any --ymodem use YMODEM protocol -Z, --zmodem use ZMODEM protocol