I'm too lazy to look and the code and fix it myself, so I'm just gonna leave it here:
> GrfCL.exe -breakOnExceptions true -extractRgz file.rgz .
fires -shellopen nevertheless.
Also if file.rgz is not found, it throws an exception:
#Log : Breaking on exceptions = True
// GRF Error Handler has thrown an exception :
// Error level : Warning
// Message :
Could not find file 'F:\RAGNAROK ONLINE\CLIENT\TOOLS\GRF Editor v1.2.6\GrfCL\file.rgz'.
#Log : Extracted RGZ to file.rgz
but does not break.
Both bugs are little annoying, especially when processing a huge amount of files (every rgz unpacked = lost application focus; no chance to really spot missing files - need to check for them in shell script instead)
Almost forgot, using v.1.2.6