Bardnet# manually list files to use:
mkvmerge -o sequential_layout.mkv '[' input1.mp4 input2.mp4 input3.mp4 ']'
# let shell expand your wildcard:
mkvmerge -o sequential_layout.mkv '[' input?.mp4 ']'
# or even:
mkvmerge -o sequential_layout.mkv '[' *.mp4 ']'
