Provided by: postgresql-9.5_9.5.25-0ubuntu0.16.04.1_amd64 
NAME
initdb - create a new PostgreSQL database cluster
SYNOPSIS
initdb [option...] [--pgdata | -D] directory
DESCRIPTION
initdb creates a new PostgreSQL database cluster. A database cluster is a collection of databases that
are managed by a single server instance.
Creating a database cluster consists of creating the directories in which the database data will live,
generating the shared catalog tables (tables that belong to the whole cluster rather than to any
particular database), and creating the template1 and postgres databases. When you later create a new
database, everything in the template1 database is copied. (Therefore, anything installed in template1 is
automatically copied into each database created later.) The postgres database is a default database meant
for use by users, utilities and third party applications.
Although initdb will attempt to create the specified data directory, it might not have permission if the
parent directory of the desired data directory is root-owned. To initialize in such a setup, create an
empty data directory as root, then use chown to assign ownership of that directory to the database user
account, then su to become the database user to run initdb.
initdb must be run as the user that will own the server process, because the server needs to have access
to the files and directories that initdb creates. Since the server cannot be run as root, you must not
run initdb as root either. (It will in fact refuse to do so.)
initdb initializes the database cluster's default locale and character set encoding. The character set
encoding, collation order (LC_COLLATE) and character set classes (LC_CTYPE, e.g., upper, lower, digit)
can be set separately for a database when it is created. initdb determines those settings for the
template1 database, which will serve as the default for all other databases.
To alter the default collation order or character set classes, use the --lc-collate and --lc-ctype
options. Collation orders other than C or POSIX also have a performance penalty. For these reasons it is
important to choose the right locale when running initdb.
The remaining locale categories can be changed later when the server is started. You can also use
--locale to set the default for all locale categories, including collation order and character set
classes. All server locale values (lc_*) can be displayed via SHOW ALL. More details can be found in
Section 22.1, “Locale Support”, in the documentation.
To alter the default encoding, use the --encoding. More details can be found in Section 22.3, “Character
Set Support”, in the documentation.
OPTIONS
-A authmethod
--auth=authmethod
This option specifies the authentication method for local users used in pg_hba.conf (host and local
lines). Do not use trust unless you trust all local users on your system. trust is the default for
ease of installation.
--auth-host=authmethod
This option specifies the authentication method for local users via TCP/IP connections used in
pg_hba.conf (host lines).
--auth-local=authmethod
This option specifies the authentication method for local users via Unix-domain socket connections
used in pg_hba.conf (local lines).
-D directory
--pgdata=directory
This option specifies the directory where the database cluster should be stored. This is the only
information required by initdb, but you can avoid writing it by setting the PGDATA environment
variable, which can be convenient since the database server (postgres) can find the database
directory later by the same variable.
-E encoding
--encoding=encoding
Selects the encoding of the template database. This will also be the default encoding of any database
you create later, unless you override it there. The default is derived from the locale, or SQL_ASCII
if that does not work. The character sets supported by the PostgreSQL server are described in Section
22.3.1, “Supported Character Sets”, in the documentation.
-k
--data-checksums
Use checksums on data pages to help detect corruption by the I/O system that would otherwise be
silent. Enabling checksums may incur a noticeable performance penalty. This option can only be set
during initialization, and cannot be changed later. If set, checksums are calculated for all objects,
in all databases.
--locale=locale
Sets the default locale for the database cluster. If this option is not specified, the locale is
inherited from the environment that initdb runs in. Locale support is described in Section 22.1,
“Locale Support”, in the documentation.
--lc-collate=locale
--lc-ctype=locale
--lc-messages=locale
--lc-monetary=locale
--lc-numeric=locale
--lc-time=locale
Like --locale, but only sets the locale in the specified category.
--no-locale
Equivalent to --locale=C.
-N
--nosync
By default, initdb will wait for all files to be written safely to disk. This option causes initdb to
return without waiting, which is faster, but means that a subsequent operating system crash can leave
the data directory corrupt. Generally, this option is useful for testing, but should not be used when
creating a production installation.
--pwfile=filename
Makes initdb read the database superuser's password from a file. The first line of the file is taken
as the password.
-S
--sync-only
Safely write all database files to disk and exit. This does not perform any of the normal initdb
operations.
-T CFG
--text-search-config=CFG
Sets the default text search configuration. See default_text_search_config for further information.
-U username
--username=username
Selects the user name of the database superuser. This defaults to the name of the effective user
running initdb. It is really not important what the superuser's name is, but one might choose to keep
the customary name postgres, even if the operating system user's name is different.
-W
--pwprompt
Makes initdb prompt for a password to give the database superuser. If you don't plan on using
password authentication, this is not important. Otherwise you won't be able to use password
authentication until you have a password set up.
-X directory
--xlogdir=directory
This option specifies the directory where the transaction log should be stored.
Other, less commonly used, options are also available:
-d
--debug
Print debugging output from the bootstrap backend and a few other messages of lesser interest for the
general public. The bootstrap backend is the program initdb uses to create the catalog tables. This
option generates a tremendous amount of extremely boring output.
-L directory
Specifies where initdb should find its input files to initialize the database cluster. This is
normally not necessary. You will be told if you need to specify their location explicitly.
-n
--noclean
By default, when initdb determines that an error prevented it from completely creating the database
cluster, it removes any files it might have created before discovering that it cannot finish the job.
This option inhibits tidying-up and is thus useful for debugging.
Other options:
-V
--version
Print the initdb version and exit.
-?
--help
Show help about initdb command line arguments, and exit.
ENVIRONMENT
PGDATA
Specifies the directory where the database cluster is to be stored; can be overridden using the -D
option.
TZ
Specifies the default time zone of the created database cluster. The value should be a full time zone
name (see Section 8.5.3, “Time Zones”, in the documentation).
This utility, like most other PostgreSQL utilities, also uses the environment variables supported by
libpq (see Section 31.14, “Environment Variables”, in the documentation).
NOTES
initdb can also be invoked via pg_ctl initdb.
SEE ALSO
pg_ctl(1), postgres(1)