Документация psql notes for windows users

SYNOPSIS

psql [option…] [dbname [username]]

DESCRIPTION

psql
is a terminal-based front-end to
PostgreSQL. It enables you to type in queries interactively, issue them to
Postgres-XC, and see the query results. Alternatively, input can be from a file. In addition, it provides a number of meta-commands and various shell-like features to facilitate writing scripts and automating a wide variety of tasks.

OPTIONS

-a, —echo-all

Print all input lines to standard output as they are read. This is more useful for script processing than interactive mode. This is equivalent to setting the variable
ECHO
to
all.

-A, —no-align

Switches to unaligned output mode. (The default output mode is otherwise aligned.)

-c command, —command=command

Specifies that
psql
is to execute one command string,
command, and then exit. This is useful in shell scripts. Start-up files (psqlrc
and
~/.psqlrc) are ignored with this option.

command
must be either a command string that is completely parsable by the server (i.e., it contains no
psql-specific features), or a single backslash command. Thus you cannot mix
SQL
and
psql
meta-commands with this option. To achieve that, you could pipe the string into
psql, like this:
echo ‘\x \\ SELECT * FROM foo;’ | psql. (\\
is the separator meta-command.)

If the command string contains multiple SQL commands, they are processed in a single transaction, unless there are explicit
BEGIN/COMMIT
commands included in the string to divide it into multiple transactions. This is different from the behavior when the same string is fed to
psql’s standard input. Also, only the result of the last SQL command is returned.

-d dbname, —dbname=dbname

Specifies the name of the database to connect to. This is equivalent to specifying
dbname
as the first non-option argument on the command line.

If this parameter contains an
=
sign or starts with a valid
URI
prefix (postgresql://
or
postgres://), it is treated as a
conninfo
string. See
Section 32.1, «Database Connection Control Functions», in the documentation
for more information.

-e, —echo-queries

Copy all SQL commands sent to the server to standard output as well. This is equivalent to setting the variable
ECHO
to
queries.

-E, —echo-hidden

Echo the actual queries generated by
\d
and other backslash commands. You can use this to study
psql’s internal operations. This is equivalent to setting the variable
ECHO_HIDDEN
from within
psql.

-f filename, —file=filename

Use the file
filename
as the source of commands instead of reading commands interactively. After the file is processed,
psql
terminates. This is in many ways equivalent to the meta-command
\i.

If
filename
is
—
(hyphen), then standard input is read.

Using this option is subtly different from writing
psql < filename. In general, both will do what you expect, but using
-f
enables some nice features such as error messages with line numbers. There is also a slight chance that using this option will reduce the start-up overhead. On the other hand, the variant using the shell’s input redirection is (in theory) guaranteed to yield exactly the same output you would have received had you entered everything by hand.

-F separator, —field-separator=separator

Use
separator
as the field separator for unaligned output. This is equivalent to
\pset fieldsep
or
\f.

-h hostname, —host=hostname

Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory for the Unix-domain socket.

-H, —html

Turn on
HTML
tabular output. This is equivalent to
\pset format html
or the
\H
command.

-l, —list

List all available databases, then exit. Other non-connection options are ignored. This is similar to the meta-command
\list.

-L filename, —log-file=filename

Write all query output into file
filename, in addition to the normal output destination.

-n, —no-readline

Do not use
readline
for line editing and do not use the history. This can be useful to turn off tab expansion when cutting and pasting.

-o filename, —output=filename

Put all query output into file
filename. This is equivalent to the command
\o.

-p port, —port=port

Specifies the TCP port or the local Unix-domain socket file extension on which the server is listening for connections. Defaults to the value of the
PGPORT
environment variable or, if not set, to the port specified at compile time, usually 5432.

-P assignment, —pset=assignment

Specifies printing options, in the style of
\pset. Note that here you have to separate name and value with an equal sign instead of a space. For example, to set the output format to
LaTeX, you could write
-P format=latex.

-q, —quiet

Specifies that
psql
should do its work quietly. By default, it prints welcome messages and various informational output. If this option is used, none of this happens. This is useful with the
-c
option. Within
psql
you can also set the
QUIET
variable to achieve the same effect.

-R separator, —record-separator=separator

Use
separator
as the record separator for unaligned output. This is equivalent to the
\pset recordsep
command.

-s, —single-step

Run in single-step mode. That means the user is prompted before each command is sent to the server, with the option to cancel execution as well. Use this to debug scripts.

-S, —single-line

Runs in single-line mode where a newline terminates an SQL command, as a semicolon does.

Note


This mode is provided for those who insist on it, but you are not necessarily encouraged to use it. In particular, if you mix
SQL
and meta-commands on a line the order of execution might not always be clear to the inexperienced user.

-t, —tuples-only

Turn off printing of column names and result row count footers, etc. This is equivalent to the
\t
command.

-T table_options, —table-attr=table_options

Specifies options to be placed within the
HTMLtable
tag. See
\pset
for details.

-U username, —username=username

Connect to the database as the user
username
instead of the default. (You must have permission to do so, of course.)

-v assignment, —set=assignment, —variable=assignment

Perform a variable assignment, like the
\set
meta-command. Note that you must separate name and value, if any, by an equal sign on the command line. To unset a variable, leave off the equal sign. To set a variable with an empty value, use the equal sign but leave off the value. These assignments are done during a very early stage of start-up, so variables reserved for internal purposes might get overwritten later.

-V, —version

Print the
psql
version and exit.

-w, —no-password

Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as a
.pgpass
file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to enter a password.

Note that this option will remain set for the entire session, and so it affects uses of the meta-command
\connect
as well as the initial connection attempt.

-W, —password

Force
psql
to prompt for a password before connecting to a database.

This option is never essential, since
psql
will automatically prompt for a password if the server demands password authentication. However,
psql
will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing
-W
to avoid the extra connection attempt.

Note that this option will remain set for the entire session, and so it affects uses of the meta-command
\connect
as well as the initial connection attempt.

-x, —expanded

Turn on the expanded table formatting mode. This is equivalent to the
\x
command.

-X,, —no-psqlrc

Do not read the start-up file (neither the system-wide
psqlrc
file nor the user’s
~/.psqlrc
file).

-z, —field-separator-zero

Set the field separator for unaligned output to a zero byte.

-0, —record-separator-zero

Set the record separator for unaligned output to a zero byte. This is useful for interfacing, for example, with
xargs -0.

-1, —single-transaction

When
psql
executes a script with the
-f
option, adding this option wraps
BEGIN/COMMIT
around the script to execute it as a single transaction. This ensures that either all the commands complete successfully, or no changes are applied.

If the script itself uses
BEGIN,
COMMIT, or
ROLLBACK, this option will not have the desired effects. Also, if the script contains any command that cannot be executed inside a transaction block, specifying this option will cause that command (and hence the whole transaction) to fail.

-?, —help

Show help about
psql
command line arguments, and exit.

EXIT STATUS

psql
returns 0 to the shell if it finished normally, 1 if a fatal error of its own occurs (e.g. out of memory, file not found), 2 if the connection to the server went bad and the session was not interactive, and 3 if an error occurred in a script and the variable
ON_ERROR_STOP
was set.

Connecting to a Database

psql
is a regular
Postgres-XC
client application. In order to connect to a database you need to know the name of your target database, the host name and port number of the server, and what user name you want to connect as.
psql
can be told about those parameters via command line options, namely
-d,
-h,
-p, and
-U
respectively. If an argument is found that does not belong to any option it will be interpreted as the database name (or the user name, if the database name is already given). Not all of these options are required; there are useful defaults. If you omit the host name,
psql
will connect via a Unix-domain socket to a server on the local host, or via TCP/IP to
localhost
on machines that don’t have Unix-domain sockets. The default port number is determined at compile time. Since the database server uses the same default, you will not have to specify the port in most cases. The default user name is your Unix user name, as is the default database name. Note that you cannot just connect to any database under any user name. Your database administrator should have informed you about your access rights.

When the defaults aren’t quite right, you can save yourself some typing by setting the environment variables
PGDATABASE,
PGHOST,
PGPORT
and/or
PGUSER
to appropriate values. (For additional environment variables, see
Section 32.14, «Environment Variables», in the documentation.) It is also convenient to have a
~/.pgpass
file to avoid regularly having to type in passwords. See
Section 32.15, «The Password File», in the documentation
for more information.

An alternative way to specify connection parameters is in a
conninfo
string or a
URI, which is used instead of a database name. This mechanism give you very wide control over the connection. For example:

$ psql "service=myservice sslmode=require"
$ psql postgresql://dbmaster:5433/mydb?sslmode=require

This way you can also use
LDAP
for connection parameter lookup as described in
Section 32.17, «LDAP Lookup of Connection Parameters», in the documentation. See
Section 32.1, «Database Connection Control Functions», in the documentation
for more information on all the available connection options.

If the connection could not be made for any reason (e.g., insufficient privileges, server is not running on the targeted host, etc.),
psql
will return an error and terminate.

If at least one of standard input or standard output are a terminal, then
psql
sets the client encoding to
«auto», which will detect the appropriate client encoding from the locale settings (LC_CTYPE
environment variable on Unix systems). If this doesn’t work out as expected, the client encoding can be overridden using the environment variable
PGCLIENTENCODING.

Entering SQL Commands

In normal operation,
psql
provides a prompt with the name of the database to which
psql
is currently connected, followed by the string
=>. For example:

$ psql testdb
psql (1.1)
Type "help" for help.
testdb=>

At the prompt, the user can type in
SQL
commands. Ordinarily, input lines are sent to the server when a command-terminating semicolon is reached. An end of line does not terminate a command. Thus commands can be spread over several lines for clarity. If the command was sent and executed without error, the results of the command are displayed on the screen.

Whenever a command is executed,
psql
also polls for asynchronous notification events generated by
LISTEN(7)
and
NOTIFY(7).

Meta-Commands

Anything you enter in
psql
that begins with an unquoted backslash is a
psql
meta-command that is processed by
psql
itself. These commands make
psql
more useful for administration or scripting. Meta-commands are often called slash or backslash commands.

The format of a
psql
command is the backslash, followed immediately by a command verb, then any arguments. The arguments are separated from the command verb and each other by any number of whitespace characters.

To include whitespace in an argument you can quote it with single quotes. To include a single quote in an argument, write two single quotes within single-quoted text. Anything contained in single quotes is furthermore subject to C-like substitutions for
\n
(new line),
\t
(tab),
\b
(backspace),
\r
(carriage return),
\f
(form feed),
\digits
(octal), and
\xdigits
(hexadecimal). A backslash preceding any other character within single-quoted text quotes that single character, whatever it is.

Within an argument, text that is enclosed in backquotes (`) is taken as a command line that is passed to the shell. The output of the command (with any trailing newline removed) replaces the backquoted text.

If an unquoted colon (:) followed by a
psql
variable name appears within an argument, it is replaced by the variable’s value, as described in
SQL Interpolation.

Some commands take an
SQL
identifier (such as a table name) as argument. These arguments follow the syntax rules of
SQL: Unquoted letters are forced to lowercase, while double quotes («) protect letters from case conversion and allow incorporation of whitespace into the identifier. Within double quotes, paired double quotes reduce to a single double quote in the resulting name. For example,
FOO»BAR»BAZ
is interpreted as
fooBARbaz, and
«A weird»» name»
becomes
A weird» name.

Parsing for arguments stops at the end of the line, or when another unquoted backslash is found. An unquoted backslash is taken as the beginning of a new meta-command. The special sequence
\\
(two backslashes) marks the end of arguments and continues parsing
SQL
commands, if any. That way
SQL
and
psql
commands can be freely mixed on a line. But in any case, the arguments of a meta-command cannot continue beyond the end of the line.

The following meta-commands are defined:

\a

If the current table output format is unaligned, it is switched to aligned. If it is not unaligned, it is set to unaligned. This command is kept for backwards compatibility. See
\pset
for a more general solution.

\c or \connect [ dbname [ username ] [ host ] [ port ] ]

Establishes a new connection to a
Postgres-XC
server. If the new connection is successfully made, the previous connection is closed. If any of
dbname,
username,
host
or
port
are omitted or specified as
-, the value of that parameter from the previous connection is used. If there is no previous connection, the
libpq
default for the parameter’s value is used.

If the connection attempt failed (wrong user name, access denied, etc.), the previous connection will only be kept if
psql
is in interactive mode. When executing a non-interactive script, processing will immediately stop with an error. This distinction was chosen as a user convenience against typos on the one hand, and a safety mechanism that scripts are not accidentally acting on the wrong database on the other hand.

\C [ title ]

Sets the title of any tables being printed as the result of a query or unset any such title. This command is equivalent to
\pset title title. (The name of this command derives from
«caption», as it was previously only used to set the caption in an
HTML
table.)

\cd [ directory ]

Changes the current working directory to
directory. Without argument, changes to the current user’s home directory.

Tip


To print your current working directory, use
\! pwd.

\conninfo

Outputs information about the current database connection.

\copy { table [ ( column_list ) ] | ( query ) } { from | to } { filename | stdin | stdout | pstdin | pstdout } [ with ] [ binary ] [ oids ] [ delimiter [ as ] ‘character‘ ] [ null [ as ] ‘string‘ ] [ csv [ header ] [ quote [ as ] ‘character‘ ] [ escape [ as ] ‘character‘ ] [ force quote column_list | * ] [ force not null column_list ] ]

Performs a frontend (client) copy. This is an operation that runs an
SQLCOPY(7)
command, but instead of the server reading or writing the specified file,
psql
reads or writes the file and routes the data between the server and the local file system. This means that file accessibility and privileges are those of the local user, not the server, and no SQL superuser privileges are required.

The syntax of the command is similar to that of the
SQLCOPY(7)
command. Note that, because of this, special parsing rules apply to the
\copy
command. In particular, the variable substitution rules and backslash escapes do not apply.

\copy … from stdin | to stdout
reads/writes based on the command input and output respectively. All rows are read from the same source that issued the command, continuing until
\.
is read or the stream reaches
EOF. Output is sent to the same place as command output. To read/write from
psql’s standard input or output, use
pstdin
or
pstdout. This option is useful for populating tables in-line within a SQL script file.

Tip


This operation is not as efficient as the
SQLCOPY
command because all data must pass through the client/server connection. For large amounts of data the
SQL
command might be preferable.

\copyright

Shows the copyright and distribution terms of
Postgres-XC.

\d[S+] [ pattern ]

For each relation (table, view, index, sequence, or foreign table) or composite type matching the
pattern, show all columns, their types, the tablespace (if not the default) and any special attributes such as
NOT NULL
or defaults. Associated indexes, constraints, rules, and triggers are also shown. For foreign tables, the associated foreign server is shown as well. («Matching the pattern»
is defined in
Patterns
below.)

For some types of relation,
\d
shows additional information for each column: column values for sequences, indexed expression for indexes and foreign data wrapper options for foreign tables.

The command form
\d+
is identical, except that more information is displayed: any comments associated with the columns of the table are shown, as is the presence of OIDs in the table, the view definition if the relation is a view.

By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

Note


If
\d
is used without a
pattern
argument, it is equivalent to
\dtvsE
which will show a list of all visible tables, views, sequences and foreign tables. This is purely a convenience measure.

\da[S] [ pattern ]

Lists aggregate functions, together with their return type and the data types they operate on. If
pattern
is specified, only aggregates whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

\db[+] [ pattern ]

Lists tablespaces. If
pattern
is specified, only tablespaces whose names match the pattern are shown. If
+
is appended to the command name, each object is listed with its associated permissions.

\dc[S+] [ pattern ]

Lists conversions between character-set encodings. If
pattern
is specified, only conversions whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects. If
+
is appended to the command name, each object is listed with its associated description.

\dC[+] [ pattern ]

Lists type casts. If
pattern
is specified, only casts whose source or target types match the pattern are listed. If
+
is appended to the command name, each object is listed with its associated description.

\dd[S] [ pattern ]

Shows the descriptions of objects of type
constraint,
operator class,
operator family,
rule, and
trigger. All other comments may be viewed by the respective backslash commands for those object types.

\dd
displays descriptions for objects matching the
pattern, or of visible objects of the appropriate type if no argument is given. But in either case, only objects that have a description are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

Descriptions for objects can be created with the
COMMENT(7)SQL
command.

\ddp [ pattern ]

Lists default access privilege settings. An entry is shown for each role (and schema, if applicable) for which the default privilege settings have been changed from the built-in defaults. If
pattern
is specified, only entries whose role name or schema name matches the pattern are listed.

The
ALTER DEFAULT PRIVILEGES (ALTER_DEFAULT_PRIVILEGES(7))
command is used to set default access privileges. The meaning of the privilege display is explained under
GRANT(7).

\dD[S+] [ pattern ]

Lists domains. If
pattern
is specified, only domains whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects. If
+
is appended to the command name, each object is listed with its associated permissions and description.

\dE[S+] [ pattern ], \di[S+] [ pattern ], \ds[S+] [ pattern ], \dt[S+] [ pattern ], \dv[S+] [ pattern ]

In this group of commands, the letters
E,
i,
s,
t, and
v
stand for foreign table, index, sequence, table, and view, respectively. You can specify any or all of these letters, in any order, to obtain a listing of objects of these types. For example,
\dit
lists indexes and tables. If
+
is appended to the command name, each object is listed with its physical size on disk and its associated description, if any. If
pattern
is specified, only objects whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

\des[+] [ pattern ]

Lists foreign servers (mnemonic:
«external servers»). If
pattern
is specified, only those servers whose name matches the pattern are listed. If the form
\des+
is used, a full description of each server is shown, including the server’s ACL, type, version, options, and description.

\det[+] [ pattern ]

Lists foreign tables (mnemonic:
«external tables»). If
pattern
is specified, only entries whose table name or schema name matches the pattern are listed. If the form
\det+
is used, generic options and the foreign table description are also displayed.

\deu[+] [ pattern ]

Lists user mappings (mnemonic:
«external users»). If
pattern
is specified, only those mappings whose user names match the pattern are listed. If the form
\deu+
is used, additional information about each mapping is shown.

Caution


\deu+
might also display the user name and password of the remote user, so care should be taken not to disclose them.

\dew[+] [ pattern ]

Lists foreign-data wrappers (mnemonic:
«external wrappers»). If
pattern
is specified, only those foreign-data wrappers whose name matches the pattern are listed. If the form
\dew+
is used, the ACL, options, and description of the foreign-data wrapper are also shown.

\df[antwS+] [ pattern ]

Lists functions, together with their arguments, return types, and function types, which are classified as
«agg»
(aggregate),
«normal»,
«trigger», or
«window». To display only functions of specific type(s), add the corresponding letters
a,
n,
t, or
w
to the command. If
pattern
is specified, only functions whose names match the pattern are shown. If the form
\df+
is used, additional information about each function, including volatility, language, source code and description, is shown. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

Tip


To look up functions taking arguments or returning values of a specific type, use your pager’s search capability to scroll through the
\df
output.

\dF[+] [ pattern ]

Lists text search configurations. If
pattern
is specified, only configurations whose names match the pattern are shown. If the form
\dF+
is used, a full description of each configuration is shown, including the underlying text search parser and the dictionary list for each parser token type.

\dFd[+] [ pattern ]

Lists text search dictionaries. If
pattern
is specified, only dictionaries whose names match the pattern are shown. If the form
\dFd+
is used, additional information is shown about each selected dictionary, including the underlying text search template and the option values.

\dFp[+] [ pattern ]

Lists text search parsers. If
pattern
is specified, only parsers whose names match the pattern are shown. If the form
\dFp+
is used, a full description of each parser is shown, including the underlying functions and the list of recognized token types.

\dFt[+] [ pattern ]

Lists text search templates. If
pattern
is specified, only templates whose names match the pattern are shown. If the form
\dFt+
is used, additional information is shown about each template, including the underlying function names.

\dg[+] [ pattern ]

Lists database roles. (Since the concepts of
«users»
and
«groups»
have been unified into
«roles», this command is now equivalent to
\du.) If
pattern
is specified, only those roles whose names match the pattern are listed. If the form
\dg+
is used, additional information is shown about each role; currently this adds the comment for each role.

\dl

This is an alias for
\lo_list, which shows a list of large objects.

\dL[S+] [ pattern ]

Lists procedural languages. If
pattern
is specified, only languages whose names match the pattern are listed. By default, only user-created languages are shown; supply the
S
modifier to include system objects. If
+
is appended to the command name, each language is listed with its call handler, validator, access privileges, and whether it is a system object.

\dn[S+] [ pattern ]

Lists schemas (namespaces). If
pattern
is specified, only schemas whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects. If
+
is appended to the command name, each object is listed with its associated permissions and description, if any.

\do[S] [ pattern ]

Lists operators with their operand and return types. If
pattern
is specified, only operators whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

\dO[S+] [ pattern ]

Lists collations. If
pattern
is specified, only collations whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects. If
+
is appended to the command name, each collation is listed with its associated description, if any. Note that only collations usable with the current database’s encoding are shown, so the results may vary in different databases of the same installation.

\dp [ pattern ]

Lists tables, views and sequences with their associated access privileges. If
pattern
is specified, only tables, views and sequences whose names match the pattern are listed.

The
GRANT(7)
and
REVOKE(7)
commands are used to set access privileges. The meaning of the privilege display is explained under
GRANT(7).

\drds [ role-pattern [ database-pattern ] ]

Lists defined configuration settings. These settings can be role-specific, database-specific, or both.
role-pattern
and
database-pattern
are used to select specific roles and databases to list, respectively. If omitted, or if
*
is specified, all settings are listed, including those not role-specific or database-specific, respectively.

The
ALTER ROLE (ALTER_ROLE(7))
and
ALTER DATABASE (ALTER_DATABASE(7))
commands are used to define per-role and per-database configuration settings.

\dT[S+] [ pattern ]

Lists data types. If
pattern
is specified, only types whose names match the pattern are listed. If
+
is appended to the command name, each type is listed with its internal name and size, its allowed values if it is an
enum
type, and its associated permissions. By default, only user-created objects are shown; supply a pattern or the
S
modifier to include system objects.

\du[+] [ pattern ]

Lists database roles. (Since the concepts of
«users»
and
«groups»
have been unified into
«roles», this command is now equivalent to
\dg.) If
pattern
is specified, only those roles whose names match the pattern are listed. If the form
\du+
is used, additional information is shown about each role; currently this adds the comment for each role.

\dx[+] [ pattern ]

Lists installed extensions. If
pattern
is specified, only those extensions whose names match the pattern are listed. If the form
\dx+
is used, all the objects belonging to each matching extension are listed.

\e or \edit [ filename ] [ line_number ]

If
filename
is specified, the file is edited; after the editor exits, its content is copied back to the query buffer. If no
filename
is given, the current query buffer is copied to a temporary file which is then edited in the same fashion.

The new query buffer is then re-parsed according to the normal rules of
psql, where the whole buffer is treated as a single line. (Thus you cannot make scripts this way. Use
\i
for that.) This means that if the query ends with (or contains) a semicolon, it is immediately executed. Otherwise it will merely wait in the query buffer; type semicolon or
\g
to send it, or
\r
to cancel.

If a line number is specified,
psql
will position the cursor on the specified line of the file or query buffer. Note that if a single all-digits argument is given,
psql
assumes it is a line number, not a file name.

Tip


See under
ENVIRONMENT
for how to configure and customize your editor.

\echo text [ … ]

Prints the arguments to the standard output, separated by one space and followed by a newline. This can be useful to intersperse information in the output of scripts. For example:

=> \echo `date`
Tue Oct 26 21:40:57 CEST 1999

If the first argument is an unquoted
-n
the trailing newline is not written.

Tip


If you use the
\o
command to redirect your query output you might wish to use
\qecho
instead of this command.

\ef [ function_description [ line_number ] ]

This command fetches and edits the definition of the named function, in the form of a
CREATE OR REPLACE FUNCTION
command. Editing is done in the same way as for
\edit. After the editor exits, the updated command waits in the query buffer; type semicolon or
\g
to send it, or
\r
to cancel.

The target function can be specified by name alone, or by name and arguments, for example
foo(integer, text). The argument types must be given if there is more than one function of the same name.

If no function is specified, a blank
CREATE FUNCTION
template is presented for editing.

If a line number is specified,
psql
will position the cursor on the specified line of the function body. (Note that the function body typically does not begin on the first line of the file.)

Tip


See under
ENVIRONMENT
for how to configure and customize your editor.

\encoding [ encoding ]

Sets the client character set encoding. Without an argument, this command shows the current encoding.

\f [ string ]

Sets the field separator for unaligned query output. The default is the vertical bar (|). See also
\pset
for a generic way of setting output options.

\g [ { filename | |command } ]

Sends the current query input buffer to the server and optionally stores the query’s output in
filename
or pipes the output into a separate Unix shell executing
command. A bare
\g
is virtually equivalent to a semicolon. A
\g
with argument is a
«one-shot»
alternative to the
\o
command.

\h or \help [ command ]

Gives syntax help on the specified
SQL
command. If
command
is not specified, then
psql
will list all the commands for which syntax help is available. If
command
is an asterisk (*), then syntax help on all
SQL
commands is shown.

Note


To simplify typing, commands that consists of several words do not have to be quoted. Thus it is fine to type
\help alter table.

\H

Turns on
HTML
query output format. If the
HTML
format is already on, it is switched back to the default aligned text format. This command is for compatibility and convenience, but see
\pset
about setting other output options.

\i filename

Reads input from the file
filename
and executes it as though it had been typed on the keyboard.

Note


If you want to see the lines on the screen as they are read you must set the variable
ECHO
to
all.

\ir filename

The
\ir
command is similar to
\i, but resolves relative file names differently. When executing in interactive mode, the two commands behave identically. However, when invoked from a script,
\ir
interprets file names relative to the directory in which the script is located, rather than the current working directory.

\l (or \list), \l+ (or \list+)

List the names, owners, character set encodings, and access privileges of all the databases in the server. If
+
is appended to the command name, database sizes, default tablespaces, and descriptions are also displayed. (Size information is only available for databases that the current user can connect to.)

\lo_export loid filename

Reads the large object with
OIDloid
from the database and writes it to
filename. Note that this is subtly different from the server function
lo_export, which acts with the permissions of the user that the database server runs as and on the server’s file system.

Tip


Use
\lo_list
to find out the large object’s
OID.

\lo_import filename [ comment ]

Stores the file into a
Postgres-XC
large object. Optionally, it associates the given comment with the object. Example:

foo=> \lo_import '/home/peter/pictures/photo.xcf' 'a picture of me'
lo_import 152801

The response indicates that the large object received object ID 152801, which can be used to access the newly-created large object in the future. For the sake of readability, it is recommended to always associate a human-readable comment with every object. Both OIDs and comments can be viewed with the
\lo_list
command.

Note that this command is subtly different from the server-side
lo_import
because it acts as the local user on the local file system, rather than the server’s user and file system.

\lo_list

Large object is not supported by the current
Postgres-XC.

\lo_unlink loid

Large object is not supported by the current
Postgres-XC.

\o [ {filename | |command} ]

Saves future query results to the file
filename
or pipes future results into a separate Unix shell to execute
command. If no arguments are specified, the query output will be reset to the standard output.

«Query results»
includes all tables, command responses, and notices obtained from the database server, as well as output of various backslash commands that query the database (such as
\d), but not error messages.

Tip


To intersperse text output in between query results, use
\qecho.

\p

Print the current query buffer to the standard output.

\password [ username ]

Changes the password of the specified user (by default, the current user). This command prompts for the new password, encrypts it, and sends it to the server as an
ALTER ROLE
command. This makes sure that the new password does not appear in cleartext in the command history, the server log, or elsewhere.

\prompt [ text ] name

Prompts the user to supply text, which is assigned to the variable
name. An optional prompt string,
text, can be specified. (For multiword prompts, surround the text with single quotes.)

By default,
\prompt
uses the terminal for input and output. However, if the
-f
command line switch was used,
\prompt
uses standard input and standard output.

\pset option [ value ]

This command sets options affecting the output of query result tables.
option
indicates which option is to be set. The semantics of
value
vary depending on the selected option. For some options, omitting
value
causes the option to be toggled or unset, as described under the particular option. If no such behavior is mentioned, then omitting
value
just results in the current setting being displayed.

Adjustable printing options are:

border

The
value
must be a number. In general, the higher the number the more borders and lines the tables will have, but this depends on the particular format. In
HTML
format, this will translate directly into the
border=…
attribute; in the other formats only values 0 (no border), 1 (internal dividing lines), and 2 (table frame) make sense.

columns

Sets the target width for the
wrapped
format, and also the width limit for determining whether output is wide enough to require the pager or switch to the vertical display in expanded auto mode. Zero (the default) causes the target width to be controlled by the environment variable
COLUMNS, or the detected screen width if
COLUMNS
is not set. In addition, if
columns
is zero then the
wrapped
format only affects screen output. If
columns
is nonzero then file and pipe output is wrapped to that width as well.

expanded (or x)

If
value
is specified it must be either
on
or
off, which will enable or disable expanded mode, or
auto. If
value
is omitted the command toggles between the on and off settings. When expanded mode is enabled, query results are displayed in two columns, with the column name on the left and the data on the right. This mode is useful if the data wouldn’t fit on the screen in the normal
«horizontal»
mode. In the auto setting, the expanded mode is used whenever the query output is wider than the screen, otherwise the regular mode is used. The auto setting is only effective in the aligned and wrapped formats. In other formats, it always behaves as if the expanded mode is off.

fieldsep

Specifies the field separator to be used in unaligned output format. That way one can create, for example, tab- or comma-separated output, which other programs might prefer. To set a tab as field separator, type
\pset fieldsep ‘\t’. The default field separator is
‘|’
(a vertical bar).

fieldsep_zero

Sets the field separator to use in unaligned output format to a zero byte.

footer

If
value
is specified it must be either
on
or
off
which will enable or disable display of the table footer (the
(n rows)
count). If
value
is omitted the command toggles footer display on or off.

format

Sets the output format to one of
unaligned,
aligned,
wrapped,
html,
latex, or
troff-ms. Unique abbreviations are allowed. (That would mean one letter is enough.)

unaligned
format writes all columns of a row on one line, separated by the currently active field separator. This is useful for creating output that might be intended to be read in by other programs (for example, tab-separated or comma-separated format).

aligned
format is the standard, human-readable, nicely formatted text output; this is the default.

wrapped
format is like
aligned
but wraps wide data values across lines to make the output fit in the target column width. The target width is determined as described under the
columns
option. Note that
psql
will not attempt to wrap column header titles; therefore,
wrapped
format behaves the same as
aligned
if the total width needed for column headers exceeds the target.

The
html,
latex, and
troff-ms
formats put out tables that are intended to be included in documents using the respective mark-up language. They are not complete documents! (This might not be so dramatic in
HTML, but in
LaTeX
you must have a complete document wrapper.)

linestyle

Sets the border line drawing style to one of
ascii,
old-ascii
or
unicode. Unique abbreviations are allowed. (That would mean one letter is enough.) The default setting is
ascii. This option only affects the
aligned
and
wrapped
output formats.

ascii
style uses plain
ASCII
characters. Newlines in data are shown using a
+
symbol in the right-hand margin. When the
wrapped
format wraps data from one line to the next without a newline character, a dot (.) is shown in the right-hand margin of the first line, and again in the left-hand margin of the following line.

unicode
style uses Unicode box-drawing characters. Newlines in data are shown using a carriage return symbol in the right-hand margin. When the data is wrapped from one line to the next without a newline character, an ellipsis symbol is shown in the right-hand margin of the first line, and again in the left-hand margin of the following line.

When the
border
setting is greater than zero, this option also determines the characters with which the border lines are drawn. Plain
ASCII
characters work everywhere, but Unicode characters look nicer on displays that recognize them.

null

Sets the string to be printed in place of a null value. The default is to print nothing, which can easily be mistaken for an empty string. For example, one might prefer
\pset null ‘(null)’.

numericlocale

If
value
is specified it must be either
on
or
off
which will enable or disable display of a locale-specific character to separate groups of digits to the left of the decimal marker. If
value
is omitted the command toggles between regular and locale-specific numeric output.

pager

Controls use of a pager program for query and
psql
help output. If the environment variable
PAGER
is set, the output is piped to the specified program. Otherwise a platform-dependent default (such as
more) is used.

When the
pager
option is
off, the pager program is not used. When the
pager
option is
on, the pager is used when appropriate, i.e., when the output is to a terminal and will not fit on the screen. The
pager
option can also be set to
always, which causes the pager to be used for all terminal output regardless of whether it fits on the screen.
\pset pager
without a
value
toggles pager use on and off.

recordsep

Specifies the record (line) separator to use in unaligned output format. The default is a newline character.

recordsep_zero

Sets the record separator to use in unaligned output format to a zero byte.

tableattr (or T)

Specifies attributes to be placed inside the
HTMLtable
tag in
html
output format. This could for example be
cellpadding
or
bgcolor. Note that you probably don’t want to specify
border
here, as that is already taken care of by
\pset border. If no
value
is given, the table attributes are unset.

title

Sets the table title for any subsequently printed tables. This can be used to give your output descriptive tags. If no
value
is given, the title is unset.

tuples_only (or t)

If
value
is specified it must be either
on
or
off
which will enable or disable tuples-only mode. If
value
is omitted the command toggles between regular and tuples-only output. Regular output includes extra information such as column headers, titles, and various footers. In tuples-only mode, only actual table data is shown.

Illustrations of how these different formats look can be seen in the
EXAMPLES
section.

Tip


There are various shortcut commands for
\pset. See
\a,
\C,
\H,
\t,
\T, and
\x.

Note


It is an error to call
\pset
without any arguments. In the future this case might show the current status of all printing options.

\q or \quit

Quits the
psql
program. In a script file, only execution of that script is terminated.

\qecho text [ … ]

This command is identical to
\echo
except that the output will be written to the query output channel, as set by
\o.

\r

Resets (clears) the query buffer.

\s [ filename ]

Print or save the command line history to
filename. If
filename
is omitted, the history is written to the standard output. This option is only available if
psql
is configured to use the
GNUReadline
library.

\set [ name [ value [ … ] ] ]

Sets the
psql
variable
name
to
value, or if more than one value is given, to the concatenation of all of them. If only one argument is given, the variable is set with an empty value. To unset a variable, use the
\unset
command.

\set
without any arguments displays the names and values of all currently-set
psql
variables.

Valid variable names can contain letters, digits, and underscores. See the section
Variables
below for details. Variable names are case-sensitive.

Although you are welcome to set any variable to anything you want,
psql
treats several variables as special. They are documented in the section about variables.

Note


This command is unrelated to the
SQL
command
SET(7).

\setenv [ name [ value ] ]

Sets the environment variable
name
to
value, or if the
value
is not supplied, unsets the environment variable. Example:

testdb=> \setenv PAGER less
testdb=> \setenv LESS -imx4F

\sf[+] function_description

This command fetches and shows the definition of the named function, in the form of a
CREATE OR REPLACE FUNCTION
command. The definition is printed to the current query output channel, as set by
\o.

The target function can be specified by name alone, or by name and arguments, for example
foo(integer, text). The argument types must be given if there is more than one function of the same name.

If
+
is appended to the command name, then the output lines are numbered, with the first line of the function body being line 1.

\t

Toggles the display of output column name headings and row count footer. This command is equivalent to
\pset tuples_only
and is provided for convenience.

\T table_options

Specifies attributes to be placed within the
table
tag in
HTML
output format. This command is equivalent to
\pset tableattr table_options.

\timing [ on | off ]

Without parameter, toggles a display of how long each SQL statement takes, in milliseconds. With parameter, sets same.

\unset name

Unsets (deletes) the
psql
variable
name.

\w filename, \w |command

Outputs the current query buffer to the file
filename
or pipes it to the Unix command
command.

\x [ on | off | auto ]

Sets or toggles expanded table formatting mode. As such it is equivalent to
\pset expanded.

\z [ pattern ]

Lists tables, views and sequences with their associated access privileges. If a
pattern
is specified, only tables, views and sequences whose names match the pattern are listed.

This is an alias for
\dp
(«display privileges»).

\! [ command ]

Escapes to a separate Unix shell or executes the Unix command
command. The arguments are not further interpreted; the shell will see them as-is.

\?

Shows help information about the backslash commands.

Patterns

The various
\d
commands accept a
pattern
parameter to specify the object name(s) to be displayed. In the simplest case, a pattern is just the exact name of the object. The characters within a pattern are normally folded to lower case, just as in SQL names; for example,
\dt FOO
will display the table named
foo. As in SQL names, placing double quotes around a pattern stops folding to lower case. Should you need to include an actual double quote character in a pattern, write it as a pair of double quotes within a double-quote sequence; again this is in accord with the rules for SQL quoted identifiers. For example,
\dt «FOO»»BAR»
will display the table named
FOO»BAR
(not
foo»bar). Unlike the normal rules for SQL names, you can put double quotes around just part of a pattern, for instance
\dt FOO»FOO»BAR
will display the table named
fooFOObar.

Whenever the
pattern
parameter is omitted completely, the
\d
commands display all objects that are visible in the current schema search path — this is equivalent to using
*
as the pattern. (An object is said to be
visible
if its containing schema is in the search path and no object of the same kind and name appears earlier in the search path. This is equivalent to the statement that the object can be referenced by name without explicit schema qualification.) To see all objects in the database regardless of visibility, use
*.*
as the pattern.

Within a pattern,
*
matches any sequence of characters (including no characters) and
?
matches any single character. (This notation is comparable to Unix shell file name patterns.) For example,
\dt int*
displays tables whose names begin with
int. But within double quotes,
*
and
?
lose these special meanings and are just matched literally.

A pattern that contains a dot (.) is interpreted as a schema name pattern followed by an object name pattern. For example,
\dt foo*.*bar*
displays all tables whose table name includes
bar
that are in schemas whose schema name starts with
foo. When no dot appears, then the pattern matches only objects that are visible in the current schema search path. Again, a dot within double quotes loses its special meaning and is matched literally.

Advanced users can use regular-expression notations such as character classes, for example
[0-9]
to match any digit. All regular expression special characters work as specified in
Section 9.7.3, «POSIX Regular Expressions», in the documentation, except for
.
which is taken as a separator as mentioned above,
*
which is translated to the regular-expression notation
.*,
?
which is translated to
., and
$
which is matched literally. You can emulate these pattern characters at need by writing
?
for
.,
(R+|)
for
R*, or
(R|)
for
R?.
$
is not needed as a regular-expression character since the pattern must match the whole name, unlike the usual interpretation of regular expressions (in other words,
$
is automatically appended to your pattern). Write
*
at the beginning and/or end if you don’t wish the pattern to be anchored. Note that within double quotes, all regular expression special characters lose their special meanings and are matched literally. Also, the regular expression special characters are matched literally in operator name patterns (i.e., the argument of
\do).

Advanced Features

Variables

psql
provides variable substitution features similar to common Unix command shells. Variables are simply name/value pairs, where the value can be any string of any length. The name must consist of letters (including non-Latin letters), digits, and underscores.

To set a variable, use the
psql
meta-command
\set. For example,

testdb=> \set foo bar

sets the variable
foo
to the value
bar. To retrieve the content of the variable, precede the name with a colon, for example:

testdb=> \echo :foo
bar

This works in both regular SQL commands and meta-commands; there is more detail in
SQL Interpolation, below.

If you call
\set
without a second argument, the variable is set, with an empty string as value. To unset (i.e., delete) a variable, use the command
\unset. To show the values of all variables, call
\set
without any argument.

Note

The arguments of
\set
are subject to the same substitution rules as with other commands. Thus you can construct interesting references such as
\set :foo ‘something’
and get
«soft links»
or
«variable variables»
of
Perl
or
PHP
fame, respectively. Unfortunately (or fortunately?), there is no way to do anything useful with these constructs. On the other hand,
\set bar :foo
is a perfectly valid way to copy a variable.

A number of these variables are treated specially by
psql. They represent certain option settings that can be changed at run time by altering the value of the variable, or in some cases represent changeable state of
psql. Although you can use these variables for other purposes, this is not recommended, as the program behavior might grow really strange really quickly. By convention, all specially treated variables’ names consist of all upper-case ASCII letters (and possibly digits and underscores). To ensure maximum compatibility in the future, avoid using such variable names for your own purposes. A list of all specially treated variables follows.

AUTOCOMMIT

When
on
(the default), each SQL command is automatically committed upon successful completion. To postpone commit in this mode, you must enter a
BEGIN
or
START TRANSACTION
SQL command. When
off
or unset, SQL commands are not committed until you explicitly issue
COMMIT
or
END. The autocommit-off mode works by issuing an implicit
BEGIN
for you, just before any command that is not already in a transaction block and is not itself a
BEGIN
or other transaction-control command, nor a command that cannot be executed inside a transaction block (such as
VACUUM).

Note


In autocommit-off mode, you must explicitly abandon any failed transaction by entering
ABORT
or
ROLLBACK. Also keep in mind that if you exit the session without committing, your work will be lost.

Note


The autocommit-on mode is
Postgres-XC’s traditional behavior inherited from
PostgreSQL, but autocommit-off is closer to the SQL spec. If you prefer autocommit-off, you might wish to set it in the system-wide
psqlrc
file or your
~/.psqlrc
file.

COMP_KEYWORD_CASE

Determines which letter case to use when completing an SQL key word. If set to
lower
or
upper, the completed word will be in lower or upper case, respectively. If set to
preserve-lower
or
preserve-upper
(the default), the completed word will be in the case of the word already entered, but words being completed without anything entered will be in lower or upper case, respectively.

DBNAME

The name of the database you are currently connected to. This is set every time you connect to a database (including program start-up), but can be unset.

ECHO

If set to
all, all lines entered from the keyboard or from a script are written to the standard output before they are parsed or executed. To select this behavior on program start-up, use the switch
-a. If set to
queries,
psql
merely prints all queries as they are sent to the server. The switch for this is
-e.

ECHO_HIDDEN

When this variable is set and a backslash command queries the database, the query is first shown. This way you can study the
Postgres-XC
internals and provide similar functionality in your own programs. (To select this behavior on program start-up, use the switch
-E.) If you set the variable to the value
noexec, the queries are just shown but are not actually sent to the server and executed.

ENCODING

The current client character set encoding.

FETCH_COUNT

If this variable is set to an integer value > 0, the results of
SELECT
queries are fetched and displayed in groups of that many rows, rather than the default behavior of collecting the entire result set before display. Therefore only a limited amount of memory is used, regardless of the size of the result set. Settings of 100 to 1000 are commonly used when enabling this feature. Keep in mind that when using this feature, a query might fail after having already displayed some rows.

Tip


Although you can use any output format with this feature, the default
aligned
format tends to look bad because each group of
FETCH_COUNT
rows will be formatted separately, leading to varying column widths across the row groups. The other output formats work better.

HISTCONTROL

If this variable is set to
ignorespace, lines which begin with a space are not entered into the history list. If set to a value of
ignoredups, lines matching the previous history line are not entered. A value of
ignoreboth
combines the two options. If unset, or if set to any other value than those above, all lines read in interactive mode are saved on the history list.

Note


This feature was shamelessly plagiarized from
Bash.

HISTFILE

The file name that will be used to store the history list. The default value is
~/.psql_history. For example, putting:

\set HISTFILE ~/.psql_history- :DBNAME

in
~/.psqlrc
will cause
psql
to maintain a separate history for each database.

Note


This feature was shamelessly plagiarized from
Bash.

HISTSIZE

The number of commands to store in the command history. The default value is 500.

Note


This feature was shamelessly plagiarized from
Bash.

HOST

The database server host you are currently connected to. This is set every time you connect to a database (including program start-up), but can be unset.

IGNOREEOF

If unset, sending an
EOF
character (usually
Control+D) to an interactive session of
psql
will terminate the application. If set to a numeric value, that many
EOF
characters are ignored before the application terminates. If the variable is set but has no numeric value, the default is 10.

Note


This feature was shamelessly plagiarized from
Bash.

LASTOID

The value of the last affected OID, as returned from an
INSERT
or
\lo_import
command. This variable is only guaranteed to be valid until after the result of the next
SQL
command has been displayed.

ON_ERROR_ROLLBACK

When
on, if a statement in a transaction block generates an error, the error is ignored and the transaction continues. When
interactive, such errors are only ignored in interactive sessions, and not when reading script files. When
off
(the default), a statement in a transaction block that generates an error aborts the entire transaction. The on_error_rollback-on mode works by issuing an implicit
SAVEPOINT
for you, just before each command that is in a transaction block, and rolls back to the savepoint on error.

ON_ERROR_STOP

By default, command processing continues after an error. When this variable is set, it will instead stop immediately. In interactive mode,
psql
will return to the command prompt; otherwise,
psql
will exit, returning error code 3 to distinguish this case from fatal error conditions, which are reported using error code 1. In either case, any currently running scripts (the top-level script, if any, and any other scripts which it may have in invoked) will be terminated immediately. If the top-level command string contained multiple SQL commands, processing will stop with the current command.

PORT

The database server port to which you are currently connected. This is set every time you connect to a database (including program start-up), but can be unset.

PROMPT1, PROMPT2, PROMPT3

These specify what the prompts
psql
issues should look like. See
Prompting
below.

QUIET

This variable is equivalent to the command line option
-q. It is probably not too useful in interactive mode.

SINGLELINE

This variable is equivalent to the command line option
-S.

SINGLESTEP

This variable is equivalent to the command line option
-s.

USER

The database user you are currently connected as. This is set every time you connect to a database (including program start-up), but can be unset.

VERBOSITY

This variable can be set to the values
default,
verbose, or
terse
to control the verbosity of error reports.

SQL Interpolation

A key feature of
psql
variables is that you can substitute («interpolate») them into regular
SQL
statements, as well as the arguments of meta-commands. Furthermore,
psql
provides facilities for ensuring that variable values used as SQL literals and identifiers are properly quoted. The syntax for interpolating a value without any quoting is to prepend the variable name with a colon (:). For example,

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;

would query the table
my_table. Note that this may be unsafe: the value of the variable is copied literally, so it can contain unbalanced quotes, or even backslash commands. You must make sure that it makes sense where you put it.

When a value is to be used as an SQL literal or identifier, it is safest to arrange for it to be quoted. To quote the value of a variable as an SQL literal, write a colon followed by the variable name in single quotes. To quote the value as an SQL identifier, write a colon followed by the variable name in double quotes. These constructs deal correctly with quotes and other special characters embedded within the variable value. The previous example would be more safely written this way:

testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :"foo";

Variable interpolation will not be performed within quoted
SQL
literals and identifiers. Therefore, a construction such as
‘:foo’
doesn’t work to produce a quoted literal from a variable’s value (and it would be unsafe if it did work, since it wouldn’t correctly handle quotes embedded in the value).

One example use of this mechanism is to copy the contents of a file into a table column. First load the file into a variable and then interpolate the variable’s value as a quoted string:

testdb=> \set content `cat my_file.txt`
testdb=> INSERT INTO my_table VALUES (:'content');

(Note that this still won’t work if
my_file.txt
contains NUL bytes.
psql
does not support embedded NUL bytes in variable values.)

Since colons can legally appear in SQL commands, an apparent attempt at interpolation (that is,
:name,
:’name’, or
:»name») is not replaced unless the named variable is currently set. In any case, you can escape a colon with a backslash to protect it from substitution.

The colon syntax for variables is standard
SQL
for embedded query languages, such as
ECPG. The colon syntaxes for array slices and type casts are
Postgres-XC
extensions, which can sometimes conflict with the standard usage. The colon-quote syntax for escaping a variable’s value as an SQL literal or identifier is a
psql
extension.

Prompting

The prompts
psql
issues can be customized to your preference. The three variables
PROMPT1,
PROMPT2, and
PROMPT3
contain strings and special escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued when
psql
requests a new command. Prompt 2 is issued when more input is expected during command input because the command was not terminated with a semicolon or a quote was not closed. Prompt 3 is issued when you run an
SQLCOPY
command and you are expected to type in the row values on the terminal.

The value of the selected prompt variable is printed literally, except where a percent sign (%) is encountered. Depending on the next character, certain other text is substituted instead. Defined substitutions are:

%M

The full host name (with domain name) of the database server, or
[local]
if the connection is over a Unix domain socket, or
[local:/dir/name], if the Unix domain socket is not at the compiled in default location.

%m

The host name of the database server, truncated at the first dot, or
[local]
if the connection is over a Unix domain socket.

%>

The port number at which the database server is listening.

%n

The database session user name. (The expansion of this value might change during a database session as the result of the command
SET SESSION AUTHORIZATION.)

%/

The name of the current database.

%~

Like
%/, but the output is
~
(tilde) if the database is your default database.

%#

If the session user is a database superuser, then a
#, otherwise a
>. (The expansion of this value might change during a database session as the result of the command
SET SESSION AUTHORIZATION.)

%R

In prompt 1 normally
=, but
^
if in single-line mode, and
!
if the session is disconnected from the database (which can happen if
\connect
fails). In prompt 2 the sequence is replaced by
-,
*, a single quote, a double quote, or a dollar sign, depending on whether
psql
expects more input because the command wasn’t terminated yet, because you are inside a
/* … */
comment, or because you are inside a quoted or dollar-escaped string. In prompt 3 the sequence doesn’t produce anything.

%x

Transaction status: an empty string when not in a transaction block, or
*
when in a transaction block, or
!
when in a failed transaction block, or
?
when the transaction state is indeterminate (for example, because there is no connection).

%digits

The character with the indicated octal code is substituted.

%:name:

The value of the
psql
variable
name. See the section
Variables
for details.

%`command`

The output of
command, similar to ordinary
«back-tick»
substitution.

%[ … %]

Prompts can contain terminal control characters which, for example, change the color, background, or style of the prompt text, or change the title of the terminal window. In order for the line editing features of
Readline
to work properly, these non-printing control characters must be designated as invisible by surrounding them with
%[
and
%]. Multiple pairs of these can occur within the prompt. For example:

testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '

results in a boldfaced (1;) yellow-on-black (33;40) prompt on VT100-compatible, color-capable terminals.
To insert a percent sign into your prompt, write
%%. The default prompts are
‘%/%R%# ‘
for prompts 1 and 2, and
‘>> ‘
for prompt 3.

Note

This feature was shamelessly plagiarized from
tcsh.

Command-Line Editing

psql
supports the
Readline
library for convenient line editing and retrieval. The command history is automatically saved when
psql
exits and is reloaded when
psql
starts up. Tab-completion is also supported, although the completion logic makes no claim to be an
SQL
parser. If for some reason you do not like the tab completion, you can turn it off by putting this in a file named
.inputrc
in your home directory:

$if psql
set disable-completion on
$endif

(This is not a
psql
but a
Readline
feature. Read its documentation for further details.)

ENVIRONMENT

COLUMNS

If
\pset columns
is zero, controls the width for the
wrapped
format and width for determining if wide output requires the pager or should be switched to the vertical format in expanded auto mode.

PAGER

If the query results do not fit on the screen, they are piped through this command. Typical values are
more
or
less. The default is platform-dependent. The use of the pager can be disabled by using the
\pset
command.

PGDATABASE, PGHOST, PGPORT, PGUSER

Default connection parameters (see
Section 32.14, «Environment Variables», in the documentation).

PSQL_EDITOR, EDITOR, VISUAL

Editor used by the
\e
and
\ef
commands. The variables are examined in the order listed; the first that is set is used.

The built-in default editors are
vi
on Unix systems and
notepad.exe
on Windows systems.

PSQL_EDITOR_LINENUMBER_ARG

When
\e
or
\ef
is used with a line number argument, this variable specifies the command-line argument used to pass the starting line number to the user’s editor. For editors such as
Emacs
or
vi, this is a plus sign. Include a trailing space in the value of the variable if there needs to be space between the option name and the line number. Examples:

PSQL_EDITOR_LINENUMBER_ARG='+'
PSQL_EDITOR_LINENUMBER_ARG='--line '

The default is
+
on Unix systems (corresponding to the default editor
vi, and useful for many other common editors); but there is no default on Windows systems.

PSQL_HISTORY

Alternative location for the command history file. Tilde (~) expansion is performed.

PSQLRC

Alternative location of the user’s
.psqlrc
file. Tilde (~) expansion is performed.

SHELL

Command executed by the
\!
command.

TMPDIR

Directory for storing temporary files. The default is
/tmp.

This utility, like most other
Postgres-XC
utilities, also uses the environment variables supported by
libpq
(see
Section 32.14, «Environment Variables», in the documentation).

FILES

•
Unless it is passed an
-X
or
-c
option,
psql
attempts to read and execute commands from the system-wide
psqlrc
file and the user’s
~/.psqlrc
file before starting up. (On Windows, the user’s startup file is named
%APPDATA%\postgresql\psqlrc.conf.) See
PREFIX/share/psqlrc.sample
for information on setting up the system-wide file. It could be used to set up the client or the server to taste (using the
\set
and
SET
commands).

The location of the user’s
~/.psqlrc
file can also be set explicitly via the
PSQLRC
environment setting.

•
Both the system-wide
psqlrc
file and the user’s
~/.psqlrc
file can be made
psql-version-specific by appending a dash and the
Postgres-XC
major or minor
psql
release number, for example
~/.psqlrc-9.2
or
~/.psqlrc-9.2.5. The most specific version-matching file will be read in preference to a non-version-specific file.

•
The command-line history is stored in the file
~/.psql_history, or
%APPDATA%\postgresql\psql_history
on Windows.

The location of the history file can also be set explicitly via the
PSQL_HISTORY
environment setting.

NOTES

•
psql
is only guaranteed to work smoothly with servers of the same version. That does not mean other combinations will fail outright, but subtle and not-so-subtle problems might come up. Backslash commands are particularly likely to fail if the server is of a newer version than
psql
itself. However, backslash commands of the
\d
family should work.

NOTES FOR WINDOWS USERS

psql
is built as a
«console application». Since the Windows console windows use a different encoding than the rest of the system, you must take special care when using 8-bit characters within
psql. If
psql
detects a problematic console code page, it will warn you at startup. To change the console code page, two things are necessary:

•
Set the code page by entering
cmd.exe /c chcp 1252. (1252 is a code page that is appropriate for German; replace it with your value.) If you are using Cygwin, you can put this command in
/etc/profile.

•
Set the console font to
Lucida Console, because the raster font does not work with the ANSI code page.

EXAMPLES

The first example shows how to spread a command over several lines of input. Notice the changing prompt:

testdb=> CREATE TABLE my_table (
testdb(>  first integer not null default 0,
testdb(>  second text)
testdb-> ;
CREATE TABLE

Now look at the table definition again:

testdb=> \d my_table
             Table "my_table"
 Attribute |  Type   |      Modifier
-----------+---------+--------------------
 first     | integer | not null default 0
 second    | text    |

Now we change the prompt to something more interesting:

testdb=> \set PROMPT1 '%n@%m %~%R%# '
peter@localhost testdb=>

Let’s assume you have filled the table with data and want to take a look at it:

peter@localhost testdb=> SELECT * FROM my_table;
 first | second
-------+--------
     1 | one
     2 | two
     3 | three
     4 | four
(4 rows)

You can display tables in different ways by using the
\pset
command:

peter@localhost testdb=> \pset border 2
Border style is 2.
peter@localhost testdb=> SELECT * FROM my_table;
+-------+--------+
| first | second |
+-------+--------+
|     1 | one    |
|     2 | two    |
|     3 | three  |
|     4 | four   |
+-------+--------+
(4 rows)
peter@localhost testdb=> \pset border 0
Border style is 0.
peter@localhost testdb=> SELECT * FROM my_table;
first second
----- ------
    1 one
    2 two
    3 three
    4 four
(4 rows)
peter@localhost testdb=> \pset border 1
Border style is 1.
peter@localhost testdb=> \pset format unaligned
Output format is unaligned.
peter@localhost testdb=> \pset fieldsep ","
Field separator is ",".
peter@localhost testdb=> \pset tuples_only
Showing only tuples.
peter@localhost testdb=> SELECT second, first FROM my_table;
one,1
two,2
three,3
four,4

Alternatively, use the short commands:

peter@localhost testdb=> \a \t \x
Output format is aligned.
Tuples only is off.
Expanded display is on.
peter@localhost testdb=> SELECT * FROM my_table;
-[ RECORD 1 ]-
first  | 1
second | one
-[ RECORD 2 ]-
first  | 2
second | two
-[ RECORD 3 ]-
first  | 3
second | three
-[ RECORD 4 ]-
first  | 4
second | four