1. Prepare the OS directory
bash
sudo mkdir -p /backup && sudo chown oracle:oinstall /backup
2. Connect with SQL*Plus and list containers
sql
$ sqlplus / as sysdba
SQL> show con_name
CON_NAME
------------------------------
CDB$ROOT
SQL> show pdbs
    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 ORCLPDB1                       READ WRITE NO
         4 ORCLPDB2                       READ WRITE NO
3. Create sample data in orclpdb1
sql
SQL> alter session set container = orclpdb1;
Session altered.
SQL> create user scott identified by tiger quota unlimited on users;
User created.
SQL> grant create session, create table to scott;
Grant succeeded.
SQL> create table scott.employees (id number primary key, name varchar2(50), dept varchar2(20));
Table created.
SQL> insert into scott.employees values (1,'Anna','IT');
SQL> insert into scott.employees values (2,'Erik','HR');
SQL> insert into scott.employees values (3,'Lena','Finance');
SQL> commit;
SQL> select * from scott.employees;
        ID NAME                                               DEPT
---------- -------------------------------------------------- --------------------
         1 Anna                                               IT
         2 Erik                                               HR
         3 Lena                                               Finance
4. Create the Oracle directory object (inside the PDB)
sql
SQL> create or replace directory backup_dir as '/backup';
Directory created.
SQL> grant read, write on directory backup_dir to scott;
Grant succeeded.
SQL> select directory_name, directory_path from dba_directories where directory_name='BACKUP_DIR';
DIRECTORY_NAME   DIRECTORY_PATH
---------------- ---------------
BACKUP_DIR       /backup
The directory object must be created inside the PDB, because Data Pump runs against a PDB and a CDB$ROOT directory is not visible there.
5. Run expdp against orclpdb1
expdp connects through the listener using the PDB service name, not / as sysdba (which lands in CDB$ROOT):
bash
expdp system@//localhost:1521/orclpdb1 \
  schemas=scott \
  directory=backup_dir \
  dumpfile=orclpdb1_scott.dmp \
  logfile=orclpdb1_scott_exp.log
For a full PDB export instead of one schema, replace schemas=scott with full=y.
Expected output (trimmed):
Export: Release 19.0.0.0.0 - Production
Connected to: Oracle Database 19c Enterprise Edition - Production
Starting "SYSTEM"."SYS_EXPORT_SCHEMA_01":  system/********@//localhost:1521/orclpdb1 schemas=scott directory=backup_dir dumpfile=orclpdb1_scott.dmp logfile=orclpdb1_scott_exp.log
Processing object type SCHEMA_EXPORT/TABLE/TABLE_DATA
Processing object type SCHEMA_EXPORT/TABLE/TABLE
. . exported "SCOTT"."EMPLOYEES"                         5.5 KB       3 rows
Master table "SYSTEM"."SYS_EXPORT_SCHEMA_01" successfully loaded/unloaded
Dump file set for SYSTEM.SYS_EXPORT_SCHEMA_01 is:
  /backup/orclpdb1_scott.dmp
Job "SYSTEM"."SYS_EXPORT_SCHEMA_01" successfully completed

postgres=# CREATE DATABASE pgdump_test;
CREATE DATABASE
postgres=# \c pgdump_test
psql (16.15 (Ubuntu 16.15-0ubuntu0.24.04.1), server 15.16 (Ubuntu 15.16-1.pgdg24.04+1))
You are now connected to database "pgdump_test" as user "postgres".
pgdump_test=# SELECT current_database();
 current_database
------------------
 pgdump_test
(1 row)
pgdump_test=# CREATE TABLE employees (
    employee_id   integer GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    employee_name varchar(100) NOT NULL,
    department    varchar(50),
    salary        numeric(10,2),
    joining_date  date
);
CREATE TABLE
pgdump_test=# CREATE TABLE departments (
    department_id   integer PRIMARY KEY,
    department_name varchar(50) NOT NULL,
    location        varchar(50)
);
CREATE TABLE
pgdump_test=# \dt
            List of relations
 Schema |    Name     | Type  |  Owner
--------+-------------+-------+----------
 public | departments | table | postgres
 public | employees   | table | postgres
(2 rows)
pgdump_test=# INSERT INTO employees
    (employee_name, department, salary, joining_date)
VALUES
    ('John Smith',   'Database', 75000, '2022-01-10'),
    ('Mary Jones',   'Database', 72000, '2022-03-15'),
    ('David Miller', 'Linux',    68000, '2021-06-20'),
    ('Sarah Brown',  'Cloud',    82000, '2020-11-05'),
    ('Robert Wilson','Cloud',    79000, '2023-02-12'),
    ('Lisa Taylor',  'Backup',   70000, '2022-08-17'),
    ('James Davis',  'Linux',    71000, '2021-12-01'),
    ('Emma White',   'Database', 76000, '2023-04-18'),
    ('Michael Clark','Backup',   69000, '2020-07-25'),
    ('Sophia Lewis', 'Cloud',    85000, '2024-01-08');
INSERT 0 10
pgdump_test=# INSERT INTO departments
VALUES
    (10, 'Database', 'Stockholm'),
    (20, 'Linux',    'London'),
    (30, 'Cloud',    'Frankfurt'),
    (40, 'Backup',   'Amsterdam');
INSERT 0 4
pgdump_test=# select * from employees;
 employee_id | employee_name | department |  salary  | joining_date
-------------+---------------+------------+----------+--------------
           1 | John Smith    | Database   | 75000.00 | 2022-01-10
           2 | Mary Jones    | Database   | 72000.00 | 2022-03-15
           3 | David Miller  | Linux      | 68000.00 | 2021-06-20
           4 | Sarah Brown   | Cloud      | 82000.00 | 2020-11-05
           5 | Robert Wilson | Cloud      | 79000.00 | 2023-02-12
           6 | Lisa Taylor   | Backup     | 70000.00 | 2022-08-17
           7 | James Davis   | Linux      | 71000.00 | 2021-12-01
           8 | Emma White    | Database   | 76000.00 | 2023-04-18
           9 | Michael Clark | Backup     | 69000.00 | 2020-07-25
          10 | Sophia Lewis  | Cloud      | 85000.00 | 2024-01-08
(10 rows)
pgdump_test=# select * from departments;
 department_id | department_name | location
---------------+-----------------+-----------
            10 | Database        | Stockholm
            20 | Linux           | London
            30 | Cloud           | Frankfurt
            40 | Backup          | Amsterdam
(4 rows)
pgdump_test=# \q