RMAN Error on Linux - rman: can't pen rcvcat target or it Just Hangs

You are running RMAN from the command line and the prompt will not return-or-

You receive a error similar to one of the following:
% rman: can't open rcvcat-or-
% rman: can't open target -or-
% rman: can't open nocatalog

Description
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Ensure that correct RMAN executable is being run by typing
$which rman
The output will most likely show '/usr/bin/rman'Execute RMAN by typing in the following:$ORACLE_HOME/bin/rmanAnother solution is to add $ORACLE_HOME/bin before /usr/bin in the PATH environment variable

Explanation
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Under a default REDHAT LINUX install, a KDE program called rman (a fileviewing / editing program) is installed under /usr/bin. If this is listedprior to $ORACLE_HOME/bin in the users PATH environment then it iscalled instead of Oracle RMAN.