Eagle library check

The Eagle library checker is a tool that performs a "diff" between the libraries
inside a schematic and the external libraries.
The program has been arised because, unfortunately, Eagle itself does not provide this tool.
Eagle provides a way to update the libraries inside the schematic from the external libraries,
but does not show you (neither in advance or afterwards) what has been updated.

This tool (partially) solves the problem and gives you the possibility to check for any differences
between the schematic and the libraries before updating the schematic.

The tool opens the schematic and library files in read-only mode, your data will not be altered.

The tool consist of two parts, an executable that is actually performing the "diff" and an ULP
that acts as gluecode between the Eagle userinterface and the executable.

It would have been nice if everything could have been written in an ULP but that's not possible.


This is free software, it is experimental and available under the GPLv2 license.
Despite this software is intend to be usefull, there is no warranty, use this software at your own risk.

The sourcecode


Because compiling on Linux is very easy, this is the preferred way.
Dowload the sourcecode and follow the instructions further on this page.

Mac / Windows

At this moment, there's no Mac or Windows version.
Feel free to modify the soucecode and make it work on Mac or Windows.

Version info

version 1.02 March 2015:
- Bug fix.

Version info

version 1.00 March 2015:
- First release.

Feedback to: teuniz@gmail.com


Eagle V6 or higher. At the moment of this writing, it has been tested with Eagle V6.60 Linux.
Please report if you find any problems using Eagle V7.


When searching for libraries, it uses the path set in Options -> Directories -> Libraries.
It does not check any sub-directories. If your library-directory contains sub-dirs, add them
to the path in Options -> Directories -> Libraries.


Make sure the GCC compiler is installed.
For example, on Ubuntu, open a konsole and type: apt-get install gcc

Then, just run the build script.


The executable "eaglelibcheck" must be put in the $EAGLEDIR/bin directory.
The ULP "diff-sch-lbr.ulp" must be put in the $EAGLEDIR/ulp directory.
Now you can run the ULP from inside a schematic editor window by typing: run diff-sch-lbr


In case you get the error: "An error occurred while executing external program."
and you are sure that the executable "eaglelibcheck" is present in the $EAGLEDIR/bin directory,
check your project directory and look for a file "libcheck.out". If present, open it with a text-editor
and look for error messages.


Despite this program has been made with best intentions, there is no guarantee!
Do not solely rely on this tool!
If the tool finds a difference, you can be pretty sure there is.
However, if the tool reports that no differences has been found, there still can
be differences present due to misstakes, bugs, missing checks, whatever!
If you think you found a bug, please report it.