Canorus is a free cross-platform music score editor. It supports an unlimited number and length of staffs, polyphony, a MIDI playback of notes, chord markings, lyrics, import/export filters to formats like MIDI, MusicXML, ABC Music, MusiXTeX and LilyPond
Gedit Plugin for XML Validation and Transformation
Use xmllint (from libxml2) and xsltproc (from libxslt) from within Gedit to validate an XML document.
To install:
1) Download the xmlvaltran.py and xmlvaltran.plugin files to the "~/.local/share/gedit/plugins/" directory. If the directory does not exist, create it: "mkdir -p ~/.local/share/gedit/plugins/"
2) Start or restart Gedit, and go to "Edit -> Preferences -> Plugins".
3) Select the checkbox next to "XML Validator/Transformer". ...