How to copy a table from one PostgreSQL database to another?

Here is an example bash script that copies a table from one PostgreSQL database to another:

#!/bin/bash

# Source database credentials
SRC_DB_HOST="localhost"
SRC_DB_PORT="5442"
SRC_DB_NAME="postgres"
SRC_DB_USER="myuser"
SRC_DB_PASS='mypwd'

# Destination database credentials
DEST_DB_HOST="localhost"
DEST_DB_PORT="5443"
DEST_DB_NAME="postgres"
DEST_DB_USER="myuser"
DEST_DB_PASS='mypwd'

# Table name to copy
TABLE_NAME="my_table"

# Temporary file to store the SQL dump
DUMP_FILE="/tmp/${TABLE_NAME}.sql"

# Check the table exists in the Source DB.
export PGPASSWORD=$SRC_DB_PASS
RESULT=$(psql -h ${SRC_DB_HOST} -p ${SRC_DB_PORT} -U ${SRC_DB_USER} -d ${SRC_DB_NAME} -t -c "SELECT count(1) FROM information_schema.tables WHERE table_name = '${TABLE_NAME}' ")
if [[ "$RESULT" -eq "0" ]]; then
  echo "Error: The table ${TABLE_NAME} doesn't exist in the Source DB."
  exit 1
fi

# Check the table dosn't exist in the Destination DB.
export PGPASSWORD=$DEST_DB_PASS
RESULT=$(psql -h ${DEST_DB_HOST} -p ${DEST_DB_PORT} -U ${DEST_DB_USER} -d ${DEST_DB_NAME} -t -c "SELECT count(1) FROM information_schema.tables WHERE table_name = '${TABLE_NAME}' ")
if [[ "$RESULT" -ne "0" ]]; then
  echo "Error: The table ${TABLE_NAME} exists in the Destination DB."
  exit 1
fi

# Dump the table to a SQL file
export PGPASSWORD=$SRC_DB_PASS
pg_dump -h ${SRC_DB_HOST} -p ${SRC_DB_PORT} -U ${SRC_DB_USER} -t ${TABLE_NAME} -F p ${SRC_DB_NAME} > ${DUMP_FILE}

# Restore the SQL dump to the destination database
export PGPASSWORD=$DEST_DB_PASS
psql -h ${DEST_DB_HOST} -p ${DEST_DB_PORT} -U ${DEST_DB_USER} -d ${DEST_DB_NAME} -f ${DUMP_FILE} -v ON_ERROR_STOP=1

# Check if the table was successfully copied
export PGPASSWORD=$DEST_DB_PASS
RESULT=$(psql -h ${DEST_DB_HOST} -p ${DEST_DB_PORT} -U ${DEST_DB_USER} -d ${DEST_DB_NAME} -t -c "SELECT COUNT(*) FROM ${TABLE_NAME}")
if [[ "$RESULT" -eq "0" ]]; then
  echo "Error: The table ${TABLE_NAME} could not be copied."
  exit 1
fi

# Get the number of records in the source table
export PGPASSWORD=$SRC_DB_PASS
source_count=$(psql -h ${SRC_DB_HOST} -p ${SRC_DB_PORT} -U ${SRC_DB_USER} -d ${SRC_DB_NAME} -c "SELECT COUNT(*) FROM ${TABLE_NAME}" -t)

# Get the number of records in the destination table
export PGPASSWORD=$DEST_DB_PASS
dest_count=$(psql -h ${DEST_DB_HOST} -p ${DEST_DB_PORT} -U ${DEST_DB_USER} -d ${DEST_DB_NAME} -c "SELECT COUNT(*) FROM ${TABLE_NAME}" -t)

# Check that the number of records matches
if [ "$source_count" -ne "$dest_count" ]; then
    echo "Error: The number of records in the source and destination tables ${TABLE_NAME} do not match."
    exit 1
else
    echo "Success: The table ${TABLE_NAME} was copied successfully."
fi

echo "The table was ${TABLE_NAME} successfully copied to the destination database."

You will need to modify the script to include your specific database credentials, table name, and destination database. Make sure to also set the appropriate permissions on the script to execute it.