Starting from sphinx 3.6.3, we would not distribute a separate command
line help file.  For any executable in sphinx3, you could get command
line information by simply typing command.

e.g. in sphinx 3.6.3, if you do

> sphinx3_decode

will give you a summary which look like this. 

Arguments list definition:
[NAME]			[DEFLT]		[DESCR]
-agc			none		Automatic gain control for c0 ('max' or 'none'); (max: c0 -= max-over-current-sentence(c0))
-backtrace		1		Whether detailed backtrace information (word segmentation/scores) shown in log
-beam			1.0e-55		Beam selecting active HMMs (relative to best) in each frame [0(widest)..1(narrowest)]
-bestpath		0		Whether to run bestpath DAG search after forward Viterbi pass
-bestpathlw				Language weight for bestpath DAG search (default: same as -lw)
-bestscoredir				(Mode 3) Directory for writing best score/frame (used to set beamwidth; one file/utterance)
-bestsenscrdir				When Best senone score directory.

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