The ly command

Usage:

ly [options] commands file, ...

A tool for manipulating LilyPond source files

Options

-v, --version show version number and exit
-h, --help show this help text and exit
-i, --in-place overwrite input files
-o, --output NAME
 output file name
-e, --encoding ENC
 (input) encoding (default UTF-8)
--output-encoding ENC
 output encoding (default to input encoding)
-d <variable=value>
 set a variable

The special option -- considers the remaining arguments to be file names.

Arguments

The command is one argument with semicolon-separated commands. In most cases you’ll quote the command so that it is seen as one argument.

You can specify more than one LilyPond file. If you want to process many files and write the results of the operations on each file to a separate output file, you can use two special characters in the output filename: a ‘*’ will be replaced with the full path name of the current input file (without extension), and a ‘?’ will be replaced with the input filename (without path and extension). If you don’t want to have ‘*’ or ‘?’ replaced in the output filename, you can set -d replace-pattern=false.

If you don’t specify input or output filenames, standard input is read and standard output is written to.

Commands

Informative commands that write information to standard output and do not change the file:

mode
print the mode (guessing if not given) of the document
version
print the LilyPond version, if set in the document
language
print the pitch name language, if set in the document

Commands that change the file:

indent
re-indent the file
reformat
reformat the file
translate <language>
translate the pitch names to the language
transpose <from> <to>
transpose the file like LilyPond would do, pitches are given in the ‘nederlands’ language
abs2rel
convert absolute music to relative
rel2abs
convert relative music to absolute
write [filename]
write the file to the given filename or the output variable. If the last command was an editing command, write is automatically called.

Commands that export the file to another format:

musicxml [filename]
export to MusicXML (in development, far from complete)
highlight [filename]
export the document as syntax colored HTML
hl [filename]
alias for highlight

Between commands, you can set or unset a variable using:

variable=value
set a variable to value. Special values are true, false, which are interpreted as boolean values, or digits, which will be interpreted as integer values.
variable=
unset a variable

Variables

The following variables can be set to influence the behaviour of commands. If there is a default value, it is written between brackets:

mode
mode of the file to read (default automatic) can be one of: lilypond, scheme, latex, html, docbook, texinfo.
output [-]
the output filename (also set by -o argument)
encoding [UTF-8]
encoding to read (also set by -e argument)
output-encoding
encoding to write (defaults to encoding, also set by the --output-encoding argument)
in-place [false]
whether to overwrite input files (same as -i)
backup-suffix [~]
suffix to use when editing files in-place, if set, backs up the original file before overwriting it
replace-pattern [true]
whether to replace ‘*’ and ‘?’ in the output filename.
indent-tabs [false]
whether to use tabs for indent
indent-width [2]
how many spaces for each indent level (if not using tabs)
stylesheet
filename to reference as an external stylesheet for syntax-highlighted HTML. This filename is literally used in the <link rel="stylesheet"> tag.
inline-style [false]
whether to use inline style attributes for syntax-highlighted HTML. By default a css stylesheet is embedded.
number-lines [false]
whether to add line numbers when creating syntax-highlighted HTML.

These variables influence the output of information commands:

with-filename
prints the filename next to information like version, etc. This is true by default if there is more than one file specified.

Examples

Here is an example to re-indent and transpose a LilyPond file:

ly "indent; transpose c d" -o output.ly file.ly

Examples using the ‘*’ in the output file name:

ly "transpose c d" *.ly -o '*-transposed.ly'
ly highlight *.ly -o 'html/?.html'

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