The error

SP2-0552: Bind variable "B2" not declared.

can arise when using incorrect declarations in your SQL scripts.

For example, I had the follwing in a script:

var B2 DATE;
EXEC :B2 := to_date('22.02.2018','dd.mm.yyyy');

For sqlplus to accept this string, you need to declare your string as VARCHAR2, even though you intend to use datatype DATE in your query.

Declare it as VARCHAR instead:

var B2 VARCHAR2(10);

How to load a plan from the cursor cache into the SMB

set serveroutput on
VARIABLE cnt NUMBER

-- Specifying both the SQL ID and the plan hash value:
EXECUTE :cnt := DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE( -
                    sql_id => '5abzqhtfcvr73' -
                    ,plan_hash_value =>7104589 -
                    ,fixed => 'YES' -
                    ,enabled=>'YES');


-- without a specific plan hash value:
EXECUTE :cnt := DBMS_SPM.LOAD_PLANS_FROM_CURSOR_CACHE( -
                    sql_id => '5abzqhtfcvr73' -
                    ,fixed => 'YES' -
                    ,enabled=>'YES');
print :cnt;
exit

How to recursively zip a folder and its subfolders and add password protetion+encryption

Below I am compressing all files and subfolders in the folder /home/oracle/outputfiles:

cd /home/oracle/outputfiles
zip -r --encrypt myzipfile.zip *

You will be prompted for a password, which has to be verified.
If you are located in the parent directory, use

zip -r -q myzipfile mydir

where myzipfile is the name of the resulting zip file, and mydir is the name of the directory.
The .zip extension will be added to myzipfile automatically.