Not sure what form of documentation you are trying to look at there, but here I just do "man sox" and it pops up in gory detail.
The "hyphens" you see are "-" minus signs, as with any other unix command.
Here's the info on that rate option you asked about. My first guess was that 'q' meant "quick and dirty", and l/m/h stood for "low/medium/high", and 'v' was for "very high" (quality). Looks like the man page agrees:
rate [-q|-l|-m|-h|-v] [override-options] RATE[k]
Change the audio sampling rate (i.e. resample the audio) to any given RATE (even non-integer if
this is supported by the output file format) using a quality level defined as follows:
Quality Band- Rej dB Typical Use
width
-q quick n/a ≈30 @ playback on
Fs/4 ancient hardware
-l low 80% 100 playback on old
hardware
-m medium 95% 100 audio playback
-h high 95% 125 16-bit mastering
(use with dither)
-v very high 95% 175 24-bit mastering
where Band-width is the percentage of the audio frequency band that is preserved and Rej dB is
the level of noise rejection. Increasing levels of resampling quality come at the expense of
increasing amounts of time to process the audio. If no quality option is given, the quality
level used is `high' (but see `Playing & Recording Audio' above regarding playback).
The `quick' algorithm uses cubic interpolation; all others use band-limited interpolation. By
default, all algorithms have a `linear' phase response; for `medium', `high' and `very high',
the phase response is configurable (see below).
The rate effect is invoked automatically if SoX's -r option specifies a rate that is different
to that of the input file(s). Alternatively, if this effect is given explicitly, then SoX's -r
option need not be given. For example, the following two commands are equivalent:
sox input.wav -r 48k output.wav bass -b 24
sox input.wav output.wav bass -b 24 rate 48k
though the second command is more flexible as it allows rate options to be given, and allows
the effects to be ordered arbitrarily.
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