Question Example of Concat

Here is a quick example :
OUT_FILE_NAME = d:/temp/outfile.txt
IN_FILE_MASK = d:/data/datafiles/F*.txt
FILE_SEPARATOR = \n

=> All the files *.txt found in directory d:/data/datafiles, will be concatenated and the result will be written in a single file named d:/temp/outfile.txt.
After each file's content, a Unix-like line break will be inserted.

I hope this helps.
Also, don't forget to read the Help in stambia Designer, in the action reference chapter.