dia

dia [OPTION...] [FILE...]

-h, --help
    Show summary of options

-V, --version
    Show version information

--usage
    Show brief usage summary

-v, --verbose
    Enable verbose output

-q, --quiet
    Suppress non-error messages

--nosplash
    Skip splash screen

--library=DIR
    Load shapes from directory DIR

--images=DIR
    Load pixbuf images from directory DIR

--export=FORMAT
    Export FILE to FORMAT (e.g., png, svg); optional params: ENCODING, BACKGROUND, ANTIALIAS, DPI, etc.

--size=WxH
    Set export canvas size to WIDTHxHEIGHT

--rotate=DEGREES
    Rotate export by DEGREES

--select=ID
    Select object with ID for export

--config=FILE
    Load configuration from FILE

--save-config
    Save current configuration

--disable-plugins
    Disable loading of plugins

--dot-from=FILE
    Generate .dia from Graphviz DOT file

Dia is a free, open-source application for creating technical diagrams, similar to Microsoft Visio. It supports flowcharts, UML, entity-relationship diagrams, network layouts, database models, Cisco networks, and more. Dia features an extensive library of shapes organized into sets, multi-layer support, automatic object alignment, text handling, and customizable colors/fonts.

Users can draw diagrams interactively via a graphical interface with drag-and-drop, bezier curves, and connection points. Dia stores diagrams in XML-based .dia files for easy editing. Command-line support enables batch operations like exporting to various formats (SVG, PNG, EPS, PDF, PS, WMF, VDX) without launching the GUI.

Lightweight and cross-platform (Linux, Windows, macOS), Dia is ideal for software engineers, network admins, and documentation writers. Plugins extend functionality, and it's licensed under GPL.

Primarily a GUI tool; CLI mainly for batch export/config. Complex --export options require exact syntax. No interactive editing via CLI.

dia --export=png:size=800x600 diagram.dia exports to PNG with custom size.

png, jpg, svg, eps, pdf, ps, wmf, vdx, shape (custom objects).

Created in 1998 by Alexander Larsson for GNOME. Initial release 0.1; stable 0.88 in 2001. Maintained by Dia developers; latest 0.97.4 (2014) with ongoing ports/patches.

inkscape(1), xfig(1), graphviz(1)