Rake task to import data from text file to Postgresl table.

import.rake

desc "import task"
task :import, [:username, :password, :dbname, :path] do |t, args|
  sh <<-SQL
  PGPASSWORD=#{args[:password]} psql --username=#{args[:username]} --dbname=#{args[:dbname]} << EOF
  \\copy films from #{args[:path]} (DELIMITER E'\t');
EOF
  SQL
end

output.sh

[arup@Ruby]$ cat /home/arup/Ruby/out1.txt
foo     bar     1233
asd     bvs     1236[arup@Ruby]$
[arup@Ruby]$ PGPASSWORD=postgres psql --username=postgres --dbname=postgres
psql (9.2.7)
Type "help" for help.

postgres=# select * from films;
 code  | title | did
-------+-------+------
 foo   | bar   | 1233
 asd   | bvs   | 1236
(2 rows)

postgres=# delete from films;
DELETE 2
postgres=# select * from films;
 code | title | did
------+-------+-----
(0 rows)

postgres=# \q
[arup@Ruby]$ rake import[postgres,postgres,postgres,/home/arup/Ruby/out1.txt]
  PGPASSWORD=postgres psql --username=postgres --dbname=postgres << EOF
  \copy films from /home/arup/Ruby/out1.txt (DELIMITER E'       ');
EOF
[arup@Ruby]$ PGPASSWORD=postgres psql --username=postgres --dbname=postgres
psql (9.2.7)
Type "help" for help.

postgres=# select * from films;
 code  | title | did
-------+-------+------
 foo   | bar   | 1233
 asd   | bvs   | 1236
(2 rows)

postgres=#