playrandomaudio.sh

# Loop five second sample from a random mp3 in a folder you specify
# Needs sox and coreutils that you can install with http://brew.sh/ (if you're on a mac)
# so you need to run theses two:
#     brew install sox 
#     brew install coreutils 
# 
# run in terminal like so
# bash ./playrandomaudio.sh "/path/to/folder/with/mp3s"
#

# Get the folder from the command line
FOLDER="$1"

# Pick a random file in the folder
FILE=$(find "$FOLDER" -type f|grep -i mp3|shuf -n 1)

# Set clip duration
DURATION=5

# Figure out how long the mp3 is with the help of sox
LEN=$(sox "$FILE" -n stat 2>&1|grep seconds|perl -pe 's|.*?(\d+).*|\1|')

# Set start position to a random location 
START=$(( RANDOM % $(($LEN - $DURATION)) ))

# Extract $DURATION seconds of audio start at $START with the help of sox
sox "$FILE" loop.mp3 trim $START $DURATION

# Play the file foreever.  
while [ 1 ];do play -q loop.mp3;done

# Quit by holding Ctrl-C