btag [options] path1 [path2] [path3] ...


btag is a TagLib-based command line multimedia tag editor that attempts to automate the process of tagging a lot of files at once. It uses the tags found in the supplied files as well as interactive user input to determine new values for the tags. It can also optionally rename files and directories based on those new values.

You can supply paths to files or directories to btag. Directories are recursively traversed and all files found are tagged. Directories are also handled differently in the sense that btag will attempt to keep information about the previously tagged files to provide sane defaults for all other files in the same parent directory. Only files with file extensions supported by TagLib are considered.



Don't do anything, just show what would have been done (dry run mode)

-d/--dir-rename-format format

Use format to rename the directories where the multimedia files were found

-i/--input-filter filter

Use filter as the input filter

-f/--filter filter

Use filter as both the input and the output filter


Display usage information and exit

-n/--renaming-filter filter

Use filter as the renaming filter

-o/--output-filter filter

Use filter as the input filter

-r/--file-rename-format format

Use format to rename the multimedia files

-t/--title-locale locale

Use locale for proper (although lax) locale-specific title casing


btag supports input and output filters that are applied to the text fields (artist, album and song title). Those filters can protect against basic mistakes such as duplicate whitespace. Input filters are used on the tags as they are loaded from the multimedia files. This filtered information is used to provide suggestions to the user when the interactive tagger requests information for those text fields. If an output filter is configured, the user input is then filtered, and if the filtered text does not match the user input, the user is asked for confirmation.

In most cases, the input filter should match the output filter (which is why the -f option is handy). You may choose to specify only an input filter, in which case the user input is not filtered. If you don't specify an input filter, though, the default input filter will be used.

The currently available filters are:


Provides basic filtering by removing duplicate or trailing whitespace, is the default input filter and the base for all other filters


The first character in the field is uppercased, while all others are lowercased


All characters are lowercased


The first character of each word is uppercased (with exceptions), while all others are lowercased


All characters are uppercased

The title capitalization algorithm will follow locale-specific context-insensitive rules depending on the value of the -t parameter. Note that strict title capitalization rules often depend on the context in which the words are used, the precise analysis of which is much beyond the scope of btag. The currently supported title locale specifications are:


English (default)




If a format is specified with the -r option, the tagged multimedia files are renamed accordingly. Likewise, if the -d option is used, the directory in which multimedia files were tagged is renamed according to the specified format.

The specified format is converted to a file or directory name using the following substitutions:


Artist name


Album name


Year of release


Track number (only replaced by the -r option)


Song title (only replaced by the -r option)

Renaming happens after the tags are written, and it's relative to btag's working directory.

For directory renaming, the last known artist, album and year information is used. Only directories that contain files that were tagged by btag are renamed.

btag does not prevent you from overwriting existing files using the formats described here.


Renaming filters are used to ensure that the file and directory names generated using the renaming formats (if specified) are valid (safe) in the context of the current file system. The following renaming filters are currently available:


Conservative character replacements are performed, recommended for FAT32 file systems


Generates file and directory names that should be valid in an Unix environment (default)


Using title casing with English rules and sensible renaming formats generating FAT32-safe file and directory names:

$ btag --file-rename-format '%track. %title' \
       --dir-rename-format '%album (%year)' \
       --filter title --title-locale en \
       --renaming-format conservative /path/to/myalbum

Using an input filter only:

$ btag --input-filter lower /path/to/myalbum