Linux Audio Recording Command Line Tool

1. Command line tools used

• PulseAudio service toolset (pacat, parec, paplay, etc.)
• Alsa driver toolset (arecord, aplay)
• sox audio processing tool

2. Task: Record playback and microphone at the same time

The script is as follows:

#!/bin/sh

filename=$1 # 脚本参数：保存的音频文件名
monitor=$(pacmd list | grep -e 'name:.*.monitor' | sed -e 's/\s*name: <//' | sed -e 's/>//')

# 麦克风
arecord -f S16_LE -c 2 -r 44100 $filename.1.wav &
ARECORD_PID=$!

# 回放
parec -d $monitor | sox -t raw -r 44100 -e signed-integer -L -b 16 -c 2 - $filename.2.wav &
PAREC_PID=$!

echo "recording... (press CTRL+C to end recording)"
BEGIN_TIME=$(date +%s)
END_RECORD=0

# 混音
trap "echo 'mixing audio'; kill $ARECORD_PID; kill $PAREC_PID; sleep 1; sox -m $filename.1.wav $filename.2.wav -c 1 $filename.wav; exit" 2

while [ $END_RECORD -le 1 ]
do
  COST_TIME=`expr $(date +%s) - $BEGIN_TIME`
  printf "$COST_TIME\r"
  sleep 1
done