What does the <<== in redirection mean?
sftp blah@server <<== >> test.log
What is the user trying to input to the command?
This is a here document/heredoc. From the bash man page:
This type of redirection instructs the shell to read input from the current source until a line containing only word (with no trailing blanks) is seen. All of the lines read up to that point are then used as the standard input for a command.
The format of here-documents is:
<<[-]word here-document delimiter
Example:
$ cat <<==
> Hello
> World
> ==
Gives:
Hello
World