Lmp merging issue

I have a bunch “lmp” files and would like to merge them, so I’ll have one long demo. Is it possible? Any tools I can use?

No. A demo is a recording of a single playing session.

Closest you can get (to what I think you're after) is to make a WAD and include up to 4 demos as DEMO1 to DEMO4, so your demos replace the demo loop of the original game. Depends exactly what you're after really.

(Well, there are special engines that allow demos to be recorded in pieces and then glued together (mbf, prboom, and some of the TAS engines I suppose). But in general, unless you're prepared to go to a lot of trouble, no.)

I've got a separate LMP for each map of Ultimate Doom from C O M P E T - N http://ural2.hszk.bme.hu/~ha211/compet-n/database/cn.cgi and wanted to merge them together to make a "whole game" run-demo.

Stupid said:

I've got a separate LMP for each map of Ultimate Doom from C O M P E T - N http://ural2.hszk.bme.hu/~ha211/compet-n/database/cn.cgi and wanted to merge them together to make a "whole game" run-demo.

You can find complete episode lmps there y'know. Just download the demos for all four episodes and make a batch file like so:

doom -playdemo e1
doom -playdemo e2
doom -playdemo e3
doom -playdemo e4

*just replace the e1 through e4 with the actual names of the lmps (remember not to add the .lmp extension).

How can I do it with prboom and @response file?

What do you need a response file for? Just create a new text file called playdemo.txt with the following lines:

prboom -playdemo e1
prboom -playdemo e2
prboom -playdemo e3
prboom -playdemo e4

Rename playdemo.txt to playdemo.bat

Put playdemo.bat into your prboom and doom.wad directory. Double click on playdemo.bat.

I don’t want to run prboom four times, I would like to run it once and specify list of LMPs to run in order.

For example command line will be:
prboom -width 640 -height 480 @doom.txt

And doom.txt will have:
-playdemo
e1.lmp
e2.lmp
e3.lmp
e4.lmp

In theory it should work, but after running e1.lmp prboom stops and doesn’t execute e2.lmp
Any idea why?

Because after running a demo, the program closes. This is true of the original .exe and all known ports. Unlike wad files only one demo can be loaded on the commandline at a time. Again this is also true of all ports.