## 2.3 Command line options for `convert-ly`

The program is invoked as follows:

>     convert-ly [option]… filename…

The following options can be given:

`-d, --diff-version-update`

  increase the `\version` string only if the file has actually been changed. In that case, the version header will correspond to the version after the last actual change. An unstable version number will be rounded up to the next stable version number unless that would exceed the target version number. Without this option, the version will instead reflect the last attempted conversion.

`-e, --edit`

  Apply the conversions direct to the input file, modifying it in-place. The original file is renamed as ‘`myfile.ly~`’. This backup file may be a hidden file on some operating systems.

`-b, --backup-numbered`

  When used with the ‘`-e`’ option, number the backup files so that no previous version is overwritten. The backup files may be hidden on some operating systems.

`-f, --from=from-patchlevel`

  Set the version to convert from. If this is not set, `convert-ly` will guess this, on the basis of `\version` strings in the file. E.g. ‘`--from=2.10.25`’

`-h, --help`

  Print usage help.

`-l loglevel, --loglevel=loglevel`

  Set the output verbosity to loglevel. Possible values, in upper case, are `PROGRESS` (the default), `NONE`, `WARNING`, `ERROR` and `DEBUG`.

`-n, --no-version`

  Normally, `convert-ly` adds a `\version` indicator to the output. Specifying this option suppresses this.

`-s, --show-rules`

  Show all known conversions and exit.

`-t, --to=to-patchlevel`

  Explicitly set which `\version` to convert to, otherwise the default is the most current value. It must be higher than the starting version.

  >     convert-ly --to=2.14.1 myfile.ly

To upgrade LilyPond fragments in texinfo files, use

>     convert-ly --from=… --to=… --no-version *.itely

To see the changes in the LilyPond syntax between two versions, use

>     convert-ly --from=… --to=… -s

其他语言：deutsch, español, français, magyar, italiano, 日本語。
About automatic language selection.

#### LilyPond — Usage v2.18.2 (稳定分支).