is it possible to use a Variable in the send Command in an rman runblock

Hello,

I want to use a variable for "NSR_CLIENT" in an rman run block.

current run block

run {
  allocate channel t1 type SBT_TAPE connect *;
  allocate channel t2 type SBT_TAPE connect *;
  send 'NSR_ENV=(NSR_CLIENT=myclient.ourdomain.loc,NSR_SERVER=networkerserver.ourdomain.loc,NSR_DATA_VOLUME_POOL=MyBackupPool)';
  backup filesperset 10 (archivelog all format '/ARCHIVELOG_%d_%s_%p/' NOT BACKED UP);
  release channel t1;
  release channel t2;
    }

myclient.ourdomain.loc is the hostname of my client

instaed of

NSR_CLIENT=myclient.ourdomain.loc

I would like to send something like

NSR_CLIENT=$(hostname)

$(hostname) should by solved to the hostname of the client