Tag

A simple utility to deal with media files tags. Born out of personal need tag can manipulate (read & write) media file tags as well as help renaming files based on the tags. Currently only tested with my personal music collection.

tag uses the htaglib Haskell library by Mark Karpov to access media file tag information.

Installation

At the moment using Nix package manager is the only supported method of building and installing tag. nix-build ran from the top level directory will build the project which can then, if desired, can be installed into a user profile using nix-env.

Usage

tag supports three modes of operation:

• read prints out tags from the specified media files
• write is capable of modifying media tags
• rename renames files based on media tags

read

$ tag read [-f|--format format] file

Print media tag information of the specified file(s), optionally based on a custom format. If the format is not specified prints out all of the details. Currently this is just a handful of entries the author finds most useful.

write

tag write ((-a|--artist artist) | (-t|--title title) |
           (-l|--album album) | (-c|--comment comment) |
           (-g|--genre genre) | (-y|--year year) | (-n|--track track))
           file

Alter media tag information for the specified file(s). At least one of the options needs to be specified. Hopefully the option name should be self-explanatory.

rename

$ tag rename (-f|--format format) file

Rename the file(s) based on the format specifier.

format option

Format is a user specified template format to be used with the read and rename commands. It accepts literal strings as well as variables based on the current file information. It also accepts a number of filters.

Full (low-level) details of the templating engine are available through EDE Haskell library documentation.

Literal strings can be embedded as is. For example

$ tag read --format "some text" file.mp3

prints out literal some text.

Variables

Variables can be embedded using {{ variable }} syntax. For example

$ tag read --format "{{ artist }}" file.mp3

prints out the artist of the file.

Currently supported variables based on the tags of the current file are:

• title
• artist
• album
• comment
• genre
• year
• track

There are also a few "special" variables:

• filename - file name of the current file
• filepath - the full path of the current file
• all - a special variable that evaluates to all of the known tag information

Filters

Filters use the | syntax and can be applied to both literals as well as variables.

For example:

tag read --format "{{ artist | toLower }}" file.mp3

prints out the artist in all lower case.

Currently a full list of filters is not documented.