ffmpeg documentation says that we can use dash muxer to create dash segments and manifest file with just a single command, like:
ffmpeg -re -i
With the help of this answer and documentation, Following is the way to do this in single command:
ffmpeg -i $inputFile \
-map 0:v:0 -map 0:a\?:0 -map 0:v:0 -map 0:a\?:0 -map 0:v:0 -map 0:a\?:0 -map 0:v:0 -map 0:a\?:0 -map 0:v:0 -map 0:a\?:0 -map 0:v:0 -map 0:a\?:0 \
-b:v:0 350k -c:v:0 libx264 -filter:v:0 "scale=320:-1" \
-b:v:1 1000k -c:v:1 libx264 -filter:v:1 "scale=640:-1" \
-b:v:2 3000k -c:v:2 libx264 -filter:v:2 "scale=1280:-1" \
-b:v:3 245k -c:v:3 libvpx-vp9 -filter:v:3 "scale=320:-1" \
-b:v:4 700k -c:v:4 libvpx-vp9 -filter:v:4 "scale=640:-1" \
-b:v:5 2100k -c:v:5 libvpx-vp9 -filter:v:5 "scale=1280:-1" \
-use_timeline 1 -use_template 1 -window_size 6 -adaptation_sets "id=0,streams=v id=1,streams=a" \
-hls_playlist true -f dash output/output.mpd