psql

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Name

psqlPostgreSQL interactive terminal

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 PostgreSQL, 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 rather 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.

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. To achieve that, you could pipe the string into psql, like this: echo "\x \\ select * from foo;" | psql.

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.

-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.

-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 internal 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 that you would have gotten 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 internal command \list.

-L filename

--log-file filename

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

-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

Allows you to specify printing options in the style of \pset on the command line. Note that here you have to separate name and value with an equal sign instead of a space. Thus 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

Allows you to specify options to be placed within the HTML table tag. See \pset for details.

-u

Forces psql to prompt for the user name and password before connecting to the database.

This option is deprecated, as it is conceptually flawed. (Prompting for a non-default user name and prompting for a password because the server requires it are really two different things.) You are encouraged to look at the -U and -W options instead.

-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 internal 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 just set a variable without a 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

--password

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

psql should automatically prompt for a password whenever the server requests password authentication. However, currently password request detection is not totally reliable, hence this option to force a prompt. If no password prompt is issued and the server requires password authentication, the connection attempt will fail.

This option will remain set for the entire session, even if you change the database connection with the meta-command \connect.

-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).

-?

--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 (out of memory, file not found) occurs, 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.

Usage

Connecting To A Database

psql is a regular PostgreSQL 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 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 can't 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 28.11, “Environment Variables”.) It is also convenient to have a ~/.pgpass file to avoid regularly having to type in passwords. See Section 28.12, “The Password File” for more information.

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.

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

Welcome to psql 8.1.3, the PostgreSQL interactive terminal.

Type:  \copyright for distribution terms

       \h for help with SQL commands

       \? for help with psql commands

       \g or terminate with semicolon to execute query

       \q to quit

testdb=>

At the prompt, the user may 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 and NOTIFY.

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 help make psql more useful for administration or scripting. Meta-commands are more commonly 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 into an argument you may quote it with a single quote. To include a single quote into such an argument, precede it by a backslash. Anything contained in single quotes is furthermore subject to C-like substitutions for \n (new line), \t (tab), \digits (octal), and \xdigits (hexadecimal).

If an unquoted argument begins with a colon (:), it is taken as a psql variable and the value of the variable is used as the argument instead.

Arguments that are enclosed in backquotes (`) are taken as a command line that is passed to the shell. The output of the command (with any trailing newline removed) is taken as the argument value. The above escape sequences also apply in backquotes.

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 when another unquoted backslash occurs. This 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.

\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.

\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.)

\connect (or \c) [ dbname [ username ] ]

Establishes a connection to a new database and/or under a user name. The previous connection is closed. If dbname is - the current database name is assumed.

If username is omitted the current user name is assumed.

As a special rule, \connect without any arguments will connect to the default database as the default user (as you would have gotten by starting psql without any arguments).

If the connection attempt failed (wrong user name, access denied, etc.), the previous connection will be kept if and only 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.

\copy table [ ( column_list ) ] { from | to } { filename | stdin | stdout | pstdin | pstdout } [ with ] [ oids ] [ delimiter [ as ] 'character' ] [ null [ as ] 'string' ] [ csv [ 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 SQL COPY 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 SQL COPY 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 table from stdin | 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 SQL COPY command because all data must pass through the client/server connection. For large amounts of data the SQL command may be preferable.

\copyright

Shows the copyright and distribution terms of PostgreSQL.

\d [ pattern ]

\d+ [ pattern ]

For each relation (table, view, index, or sequence) matching the pattern, show all columns, their types, the tablespace (if not the default) and any special attributes such as NOT NULL or defaults, if any. Associated indexes, constraints, rules, and triggers are also shown, as is the view definition if the relation is a view. (“Matching the pattern” is defined below.)

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.

Note

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

\da [ pattern ]

Lists all available aggregate functions, together with the data type they operate on. If pattern is specified, only aggregates whose names match the pattern are shown.

\db [ pattern ]

\db+ [ pattern ]

Lists all available 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 [ pattern ]

Lists all available conversions between character-set encodings. If pattern is specified, only conversions whose names match the pattern are listed.

\dC

Lists all available type casts.

\dd [ pattern ]

Shows the descriptions of objects matching the pattern, or of all visible objects if no argument is given. But in either case, only objects that have a description are listed. (“Object” covers aggregates, functions, operators, types, relations (tables, views, indexes, sequences, large objects), rules, and triggers.) For example:

=> \dd version

                     Object descriptions

   Schema   |  Name   |  Object  |        Description

------------+---------+----------+---------------------------

 pg_catalog | version | function | PostgreSQL version string

(1 row)

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

\dD [ pattern ]

Lists all available domains. If pattern is specified, only matching domains are shown.

\df [ pattern ]

\df+ [ pattern ]

Lists available functions, together with their argument and return types. 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 language and description, is shown.

Note

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

To reduce clutter, \df does not show data type I/O functions. This is implemented by ignoring functions that accept or return type cstring.

\dg [ pattern ]

Lists all database roles. If pattern is specified, only those roles whose names match the pattern are listed. (This command is now effectively the same as \du.)

\distvS [ pattern ]

This is not the actual command name: the letters i, s, t, v, S stand for index, sequence, table, view, and system table, respectively. You can specify any or all of these letters, in any order, to obtain a listing of all the matching objects. The letter S restricts the listing to system objects; without S, only non-system objects are shown. If + is appended to the command name, each object is listed with its associated description, if any.

If pattern is specified, only objects whose names match the pattern are listed.

\dl

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

\dn [ pattern ]

\dn+ [ pattern ]

Lists all available schemas (namespaces). If pattern (a regular expression) is specified, only schemas whose names match the pattern are listed. Non-local temporary schemas are suppressed. If + is appended to the command name, each object is listed with its associated permissions and description, if any.

\do [ pattern ]

Lists available operators with their operand and return types. If pattern is specified, only operators whose names match the pattern are listed.

\dp [ pattern ]

Produces a list of all available 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 commands GRANT and REVOKE are used to set access privileges. See GRANT for more information.

\dT [ pattern ]

\dT+ [ pattern ]

Lists all data types or only those that match pattern. The command form \dT+ shows extra information.

\du [ pattern ]

Lists all database roles, or only those that match pattern.

\edit (or \e) [ filename ]

If filename is specified, the file is edited; after the editor exits, its content is copied back to the query buffer. If no argument 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 also that if the query ends with (or rather contains) a semicolon, it is immediately executed. In other cases it will merely wait in the query buffer.

Tip

psql searches the environment variables PSQL_EDITOR, EDITOR, and VISUAL (in that order) for an editor to use. If all of them are unset, vi is used on Unix systems, notepad.exe on Windows systems.

\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 may wish to use \qecho instead of this command.

\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.

\help (or \h) [ 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.

\l (or \list)

\l+ (or \list+)

List the names, owners, and character set encodings of all the databases in the server. If + is appended to the command name, database descriptions are also displayed.

\lo_export loid filename

Reads the large object with OID loid 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 PostgreSQL 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 one ought to remember if one wants to access the object ever again. For that reason it is recommended to always associate a human-readable comment with every object. Those can then be seen 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

Shows a list of all PostgreSQL large objects currently stored in the database, along with any comments provided for them.

\lo_unlink loid

Deletes the large object with OID loid from the database.

Tip

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

\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.

\pset parameter [ value ]

This command sets options affecting the output of query result tables. parameter describes which option is to be set. The semantics of value depend thereon.

Adjustable printing options are:

format

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

Unaligned” writes all columns of a row on a line, separated by the currently active field separator. This is intended to create output that might be intended to be read in by other programs (tab-separated, comma-separated). “Aligned” mode is the standard, human-readable, nicely formatted text output that is default. The “HTML” and “LaTeX” modes 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.)

border

The second argument 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 mode, this will translate directly into the border=... attribute, in the others only values 0 (no border), 1 (internal dividing lines), and 2 (table frame) make sense.

expanded (or x)

Toggles between regular and expanded format. When expanded format 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.

Expanded mode is supported by all four output formats.

null

The second argument is a string that should be printed whenever a column is null. The default is not to print anything, which can easily be mistaken for, say, an empty string. Thus, one might choose to write \pset null '(null)'.

fieldsep

Specifies the field separator to be used in unaligned output mode. 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).

footer

Toggles the display of the default footer (x rows).

numericlocale

Toggles the display of a locale-aware character to separate groups of digits to the left of the decimal marker. It also enables a locale-aware decimal marker.

recordsep

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

tuples_only (or t)

Toggles between tuples only and full display. Full display may show extra information such as column headers, titles, and various footers. In tuples only mode, only actual table data is shown.

title [ text ]

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

tableattr (or T) [ text ]

Allows you to specify any attributes to be placed inside the HTML table tag. 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.

pager

Controls use of a pager 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 is off, the pager is not used. When the pager is on, the pager is used only when appropriate, i.e. the output is to a terminal and will not fit on the screen. (psql does not do a perfect job of estimating when to use the pager.) \pset pager turns the pager on and off. Pager can also be set to always, which causes the pager to be always used.

Illustrations on 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 arguments. In the future this call might show the current status of all printing options.

\q

Quits the psql program.

\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 GNU Readline library.

\set [ name [ value [ ... ] ] ]

Sets the internal variable name to value or, if more than one value is given, to the concatenation of all of them. If no second argument is given, the variable is just set with no value. To unset a variable, use the \unset command.

Valid variable names can contain characters, 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 totally separate from the SQL command SET.

\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

Allows you to specify attributes to be placed within the table tag in HTML tabular output mode. This command is equivalent to \pset tableattr table_options.

\timing

Toggles a display of how long each SQL statement takes, in milliseconds.

\w {filename | |command}

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

\x

Toggles expanded table formatting mode. As such it is equivalent to <span style="font-family: 'Courier New'; colo