ECATT variables

Hi

There are special read-only eCATT variables, which can also be used in command editor. e.g. &YEARB, &YEARA, &YEAR, &VARID, &USER, &TIME, &SYSTEM, &SUBRC, &SCRIPTVERSION, &SCRIPTNAME, &SAPRL, &REFVERSION, &REFNAME, &REFLEVEL, &OPSYS, &MSX, &MST, &MSN, &MSI, &MSG, &MS4, &MS3, &MS2, &MS1, &M04, &M03, &M02, &M01, &LPC, &LOGID, &LANGUAGE, &HOST, &EXCEPTION, &DBSYS, &DATE, &CLIENT etc.

May i know meaning of these variables and which variable we are using in ECATT chain of transactions.

I need answer for this question as early as possible. Marks assured.

Thanks,

Anil