To upload a file on the shell via FTP (https://en.wikipedia.org/wiki/File_Transfer_Protocol) you can use the wput command.
Therefor you have to install it with your systems package manager (aptitude in this example):
$> sudo apt-get install wput
Now you can upload files like that:
$> wput loacalfiletoupload ftp://user:password@host/path/to/target/on/remote/host
Attention: The target path have to be relative to the FTP-users home directory!
You will get an output like that:
--17:24:10-- `/home/sheldon/Downloads/3.png' => ftp://sheldon:email@example.com:21/3.png Connecting to 184.108.40.206:21... connected! Logging in as sheldon ... Logged in! Length: 117,130 93% [===========================================================================================================> ] 109,568 17:24:11 (3.png) - `232.6K/s'  FINISHED --17:24:11-- Transfered 117,130 bytes in 1 file at 107.2K/s