Scripts to get the maximum amplitude from audio files and plot histogram

get-audio-max.sh

#!/bin/bash

AUDIODIR=$1

helpmsg="get-audio-max.sh <input directory>"

[[ -n "$AUDIODIR" ]] || \
  { 
    echo "You must inform the input directory with the RAW audio files"; 
    echo $helpmsg; 
    exit 1; 
  }

[[ ${AUDIODIR,,} == "--help" ]] && { echo $helpmsg; exit 1; }

type sox1 >/dev/null 2>&1 || \
  { 
    echo "You must install 'sox' first.";
    echo "Use something like 'sudo yum -y install sox' or 'sudo apt-get install sox'"; 
    exit 1; 
  }

find $AUDIODIR -name "*.wav" -exec sox {} -n stat 2>&1 \; | grep "Maximum amplitude" | sed -r "s/\s+//g" | cut -d":" -f 2

plot-histogram.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import matplotlib.pyplot as plt
import sys

values = []
for line in sys.stdin:
    values.append(float(line))

plt.xlabel('Metric')
plt.ylabel('Frequency')
plt.title('Histogram')
plt.hist(values, bins=100, facecolor='blue', normed=True, cumulative=True)

plt.show()

You can show the histogram by running:
./get-audio-max.sh audio_dir | ./plot-histogram.py