How can I upload (FTP) files to server in a Bash script?

Question

I'm trying to write a Bash script that uploads a file to a server. How can I achieve this? Is a Bash script the right thing to use for this?

Answer 1

Below are two answers. First is a suggestion to use a more secure/flexible solution like ssh/scp/sftp. Second is an explanation of how to run ftp in batch mode.

A secure solution:

You really should use SSH/SCP/SFTP for this rather than FTP. SSH/SCP have the benefits of being more secure and working with public/private keys which allows it to run without a username or password.

You can send a single file:

scp <file to upload> <username>@<hostname>:<destination path>

Or a whole directory:

scp -r <directory to upload> <username>@<hostname>:<destination path>

For more details on setting up keys and moving files to the server with RSYNC, which is useful if you have a lot of files to move, or if you sometimes get just one new file among a set of random files, take a look at:

http://troy.jdmz.net/rsync/index.html

You can also execute a single command after sshing into a server:

From man ssh

ssh [...snipped...] hostname [command] If command is specified, it is executed on the remote host instead of a login shell.

So, an example command is:

ssh [email protected] bunzip file_just_sent.bz2

If you can use SFTP with keys to gain the benefit of a secured connection, there are two tricks I've used to execute commands.

First, you can pass commands using echo and pipe

echo "put files*.xml" | sftp -p -i ~/.ssh/key_name [email protected]

You can also use a batchfile with the -b parameter:

sftp -b batchfile.txt ~/.ssh/key_name [email protected]

An FTP solution, if you really need it:

If you understand that FTP is insecure and more limited and you really really want to script it...

There's a great article on this at http://www.stratigery.com/scripting.ftp.html

#!/bin/sh
HOST='ftp.example.com'
USER='yourid'
PASSWD='yourpw'
FILE='file.txt'

ftp -n $HOST <<END_SCRIPT
quote USER $USER
quote PASS $PASSWD
binary
put $FILE
quit
END_SCRIPT
exit 0

The -n to ftp ensures that the command won't try to get the password from the current terminal. The other fancy part is the use of a heredoc: the <<END_SCRIPT starts the heredoc and then that exact same END_SCRIPT on the beginning of the line by itself ends the heredoc. The binary command will set it to binary mode which helps if you are transferring something other than a text file.