Darren Mulholland

Aspirationally lazy. Looking forward to a future where work is something children learn about in history books.


A fast command line utility for joining MP3 files.

MP3Cat is a simple command line utility for concatenating MP3 files without re-encoding. It supports both constant bit rate (CBR) and variable bit rate (VBR) MP3 files.


Run mp3cat --help to view the application's command line help:


  This tool concatenates MP3 files without re-encoding. It
  can join constant bit-rate (CBR) files, variable bit-rate
  (VBR) files, or a mixture of both.

  If a set of input CBR files share the same bit-rate, the
  output file will also be CBR; if the input files have
  different bit-rates, the output file will be VBR.

  [files]                 List of files to merge.

  -c, --copy-meta <n>     Copy ID3 metadata from the n-th input file.
  -d, --dir <path>        Directory of files to merge.
  -i, --interlace <path>  Interlace a spacer file.
  -o, --out <path>        Output filepath.

  -f, --force             Overwrite an existing output file.
  -h, --help              Display this help text and exit.
  -q, --quiet             Run in quiet mode.
  -v, --version           Display the version number.

Files to be merged can be specified as a list of filenames:

$ mp3cat one.mp3 two.mp3 three.mp3

Alternatively, an entire directory of .mp3 files can be merged:

$ mp3cat --dir /path/to/directory


MP3Cat is written in Go. If you have a Go compiler installed you can run:

$ go get github.com/dmulholl/mp3cat

This will download, compile, and install the latest version of the application to your $GOPATH/bin directory.

You can find the source files on Github.


This work has been placed in the public domain.