It looks like redirection part is the weak point of current DOSBox.
For example, I made a text file which contains debugger commands like this:
------------------- input.txt ------------------
p
r cx
10
-----------------------------------------------
Then I redirected this file as an input to debug.exe(Windows DOS debugger) like this:
c:\winnt\system32\debug.exe < input.txt

On command window of Windows, it works.
On DOSBox, it doesn't work!

p.s. I suggest that DOSBox had better support copy to / paste from clipboard feature in next version...it's my hope