Tape backups 19c database

Dear Experts,

We are validating our tape backups. We are unable to get output for "list backup" command.

Below works and gave output

run {
ALLOCATE CHANNEL CH1 DEVICE TYPE sbt_tape parms 'SBT_LIBRARY=/opt/omni/lib/libob2oracle8_64bit.so,
ENV=(OB2BARTYPE=Oracle8,OB2APPNAME=uatcdb2,OB2BARLIST=UAT_ERP_19C_New)';
restore database preview;
}

Below gives error. We tried multiple times,how can we get list of backups. Is there any alternative when we connect to tape channels? Please suggest.

RMAN> run {
ALLOCATE CHANNEL CH1 DEVICE TYPE sbt_tape parms 'SBT_LIBRARY=/opt/omni/lib/libob2oracle8_64bit.so,
ENV=(OB2BARTYPE=Oracle8,OB2APPNAME=uatcdb2,OB2BARLIST=UAT_ERP_19C_New)';
list backup;
}2> 3> 4>
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00558: error encountered while parsing input commands
RMAN-01009: syntax error: found "list": expecting one of: "advise, allocate, alter, analyze, associate statistics, audit, backup, begin, @, call, catalog, change, comment, commit, configure, convert, copy, create, crosscheck, declare, delete, delete from, describe, describe catalog, disassociate statistics, drop, drop database, duplicate, execute, explain plan, flashback, flashback table, grant, host, insert, lock, merge, mount, noaudit, open, purge, recover, release, rename, repair, report, reset, restore, resync, revoke, rollback, savepoint, select, send, set, set constraint, set role,