With the COMPARE command you can compare the content of a SIMATIC app file with content of a SIMATIC PLC.
With the --mode option, you can define the verbosity of the result of the compare shown:
minimal: Only a summary is shown.delta: Only changed blocks and the summary is shown.all: All blocks are shown and the summary is shown.
Note
Source code is not loaded to the PLC with each download. Therefore, when using the COMPARE command, it can only detect differences on an abstract level based on timestamps and signatures of data and code blocks. It cannot provide a detailed difference of source lines.
Additionally, it's worth noting that the COMPARE command may omit certain technical differences for clarity, so there may be some differences that are not shown. Therefore, even if the COMPARE command shows an "equal" result, there may still be load operations executed during a download.