gbak:legal switches are:
-B(ACKUP_DATABASE) backup database to file
-BU(FFERS) override page buffers default
-C(REATE_DATABASE) create database from backup file
-CO(NVERT) backup external files as tables
-E(XPAND) no data compression
-FA(CTOR) blocking factor
-G(ARBAGE_COLLECT) inhibit garbage collection
-I(NACTIVE) deactivate indexes during restore
-IG(NORE) ignore bad checksums
-K(ILL) restore without creating shadows
-L(IMBO) ignore transactions in limbo
-M(ETA_DATA) backup metadata only
-MO(DE) <access> "read_only" or "read_write" access
-N(O_VALIDITY) do not restore database validity conditions
-NT Non-Transportable backup file format
-O(NE_AT_A_TIME) restore one table at a time
-OL(D_DESCRIPTIONS) save old style metadata descriptions
-P(AGE_SIZE) override default page size
-PAS(SWORD) Firebird password
-REP(LACE_DATABASE) replace database from backup file
-RO(LE) Firebird SQL role
-SE(RVICE) use services manager
-T(RANSPORTABLE) transportable backup -- data in XDR format
-USE_(ALL_SPACE) do not reserve space for record versions
-USER Firebird user name
-V(ERIFY) report each action taken
-Y <path> redirect/suppress status message output
-Z print version number
