One-liner for increasing sound volume for recorded files on Linux (make sure ffmpeg is installed): for file in *.3gp; do ffmpeg -i "$file" -af "volume=15.0" ./conv/"${file%.3gp}".mp3; done The line above will increase sound 15X for all files with .3gp extension in the current directory and saves the resulting .mp3 files into ./conv subdirectory (make sure it exists).
test automation, scripting, system administration, etc.