@EAWRITE

@EAWRITE[filename, EAname, [value]]:  Creates or updates the extended 
attribute named EAname for the specified file.  If the value is not 
included, the extended attribute is deleted.  Returns "0" for success or 
"-1" for failure.  This function can only write EAs stored as text; it 
cannot write binary EAs. 

Wildcards cannot be used in the file name and the filename must be in 
quotes if it contains whitespace or special characters. 

For example, to set the .SUBJECT extended attribute for README.TXT (enter 
this on one line): 

        if %@eawrite[readme.txt,.subject,Installation notes for
        latest version] != 0 echo EAWRITE failed!