Get length of .wav from sox output

I need to get the length of a .wav file.

Using:

sox output.wav -n stat

Gives:

Samples read:            449718
Length (seconds):     28.107375
Scaled by:         2147483647.0
Maximum amplitude:     0.999969
Minimum amplitude:    -0.999969
Midline amplitude:     0.000000
Mean    norm:          0.145530
Mean    amplitude:     0.000291
RMS     amplitude:     0.249847
Maximum delta:         1.316925
Minimum delta:         0.000000
Mean    delta:         0.033336
RMS     delta:         0.064767
Rough   frequency:          660
Volume adjustment:        1.000

How do I use grep or some other method to only output the value of the length in the second column, i.e. 28.107375?

Thanks

There is a better way:

soxi -D out.wav

The stat effect sends its output to stderr, use 2>&1 to redirect to stdout. Use sed to extract the relevant bits:

sox out.wav -n stat 2>&1 | sed -n 's#^Length (seconds):[^0-9]*\([0-9.]*\)$#\1#p'