BusyBox已集成命令tftp，可通过tftp上传或下载文件：
Usage: tftp [OPTIONS] HOST [PORT]
Transfer a file from/to tftp server
-l FILE Local FILE
-r FILE Remote FILE
-g Get file
-p Put file
-b SIZE Transfer blocks of SIZE octets
上传文件：
tftp -p -l local.sh 192.168.1.222
下载文件：
tftp -g -r remote.sh 192.168.1.222