linux way to convert mp3 stereo to mono?

I know how to do it in microsoft windows using Audacity to convert a mp3 audio file from stereo to mono, but it's a few mouse clicks and time consuming if you want to do many. Is there a program in Linux that provides a way such that I can batch script the commands to convert my folder of some 1000 mp3 files? For example : some_sound_program.x --convert-stereo-to-mono --input file1.mp3 --output file1_mono.mp3 some_sound_program.x --convert-stereo-to-mono --input file2.mp3 --output file2_mono.mp3 {and so on}