NLS_LANG AL32UTF8/UTF8 for Oracle database
In the original tutorial:

export NLS_LANG=`$ORACLE_HOME/bin/nls_lang.sh`


Notice the backticks. The value of NLS_LANG variable should be the output of the above command, not the file name with absolute path. Just set the value of NLS_LANG, as you already did:

export NLS_LANG=AMERICAN_AMERICA.AL32UTF8