\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 aPostgreSQL server. If the new connection is successfully made, the previous connection is closed. If any ofdbname,username,host orport are omitted or specified as-, the value of that parameter from the previous connection is used. If there is no previous connection, thelibpq 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 ifpsql 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 titletitle. (The name of this command derives from"caption", as it was previously only used to set the caption in anHTML table.)

\cd [directory ]

Changes the current working directory todirectory. 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' | program'command' | stdin | stdout | pstdin | pstdout } [ [ with ] (option [, ...] ) ]

Performs a frontend (client) copy. This is an operation that runs anSQLCOPY 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.

Whenprogram is specified,command is executed bypsql and the data passed from or tocommand is routed between the server and the client. Again, the execution privileges are those of the local user, not the server, and no SQL superuser privileges are required.

For\copy ... from stdin, data rows are read from the same source that issued the command, continuing until\. is read or the stream reachesEOF. This option is useful for populating tables in-line within a SQL script file. For\copy ... to stdout, output is sent to the same place aspsql command output, and theCOPYcount command status is not printed (since it might be confused with a data row). To read/writepsql's standard input or output regardless of the current command source or\o option, writefrom pstdin orto pstdout.

The syntax of this command is similar to that of theSQLCOPY command. All options other than the data source/destination are as specified forCOPY. Because of this, special parsing rules apply to the\copy command. In particular,psql's variable substitution rules and backslash escapes do not apply.

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

\copyright

Shows the copyright and distribution terms ofPostgreSQL.

\d[S+] [pattern ]

For each relation (table, view, index, sequence, or foreign table) or composite type matching thepattern, show all columns, their types, the tablespace (if not the default) and any special attributes such asNOT 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 inPatterns 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, a non-defaultreplica identity setting.

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

Note: If\d is used without apattern 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. Ifpattern is specified, only aggregates whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects.

\db[+] [pattern ]

Lists tablespaces. Ifpattern 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. Ifpattern is specified, only conversions whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS 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. Ifpattern 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 typeconstraint,operator class,operator family,rule, andtrigger. All other comments may be viewed by the respective backslash commands for those object types.

\dd displays descriptions for objects matching thepattern, 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 theS modifier to include system objects.

Descriptions for objects can be created with theCOMMENTSQL 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. Ifpattern is specified, only entries whose role name or schema name matches the pattern are listed.

TheALTER DEFAULT PRIVILEGES command is used to set default access privileges. The meaning of the privilege display is explained underGRANT.

\dD[S+] [pattern ]

Lists domains. Ifpattern is specified, only domains whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or theS 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 ]
\dm[S+] [pattern ]
\ds[S+] [pattern ]
\dt[S+] [pattern ]
\dv[S+] [pattern ]

In this group of commands, the lettersE,i,m,s,t, andv stand for foreign table, index, materialized view, 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. Ifpattern is specified, only objects whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects.

\des[+] [pattern ]

Lists foreign servers (mnemonic:"external servers"). Ifpattern 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"). Ifpattern 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"). Ifpattern 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"). Ifpattern 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 lettersa,n,t, orw to the command. Ifpattern is specified, only functions whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects. If the form\df+ is used, additional information about each function is shown, including security classification, volatility, owner, language, source code and description.

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. Ifpattern 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. Ifpattern 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. Ifpattern 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. Ifpattern 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.) Ifpattern 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. Ifpattern is specified, only languages whose names match the pattern are listed. By default, only user-created languages are shown; supply theS 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). Ifpattern is specified, only schemas whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS 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 result types. Ifpattern is specified, only operators whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS modifier to include system objects. If+ is appended to the command name, additional information about each operator is shown, currently just the name of the underlying function.

\dO[S+] [pattern ]

Lists collations. Ifpattern is specified, only collations whose names match the pattern are listed. By default, only user-created objects are shown; supply a pattern or theS 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. Ifpattern is specified, only tables, views and sequences whose names match the pattern are listed.

TheGRANT andREVOKE commands are used to set access privileges. The meaning of the privilege display is explained underGRANT.

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

Lists defined configuration settings. These settings can be role-specific, database-specific, or both.role-pattern anddatabase-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.

TheALTER ROLE andALTER DATABASE commands are used to define per-role and per-database configuration settings.

\dT[S+] [pattern ]

Lists data types. Ifpattern 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 anenum type, and its associated permissions. By default, only user-created objects are shown; supply a pattern or theS 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.) Ifpattern 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. Ifpattern 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.

\dy[+] [pattern ]

Lists event triggers. Ifpattern is specified, only those event triggers whose names match the pattern are listed. If+ is appended to the command name, each object is listed with its associated description.

\e or\edit [filename] [line_number]

Iffilename is specified, the file is edited; after the editor exits, its content is copied back to the query buffer. If nofilename 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 ofpsql, 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 underEnvironment for how to configure and customize your editor.

\echotext [ ... ]

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 aCREATE 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 examplefoo(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 blankCREATE 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 underEnvironment 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 ]
\g [ |command ]

Sends the current query input buffer to the server, and optionally stores the query's output infilename or pipes the output to the shell commandcommand. The file or command is written to only if the query successfully returns zero or more tuples, not if the query fails or is a non-data-returning SQL command.

A bare\g is essentially equivalent to a semicolon. A\g with argument is a"one-shot" alternative to the\o command.

\gset [prefix ]

Sends the current query input buffer to the server and stores the query's output intopsql variables (seeVariables). The query to be executed must return exactly one row. Each column of the row is stored into a separate variable, named the same as the column. For example:

=>SELECT 'hello' AS var1, 10 AS var2->\gset=>\echo :var1 :var2hello 10

If you specify aprefix, that string is prepended to the query's column names to create the variable names to use:

=>SELECT 'hello' AS var1, 10 AS var2->\gset result_=>\echo :result_var1 :result_var2hello 10

If a column result is NULL, the corresponding variable is unset rather than being set.

If the query fails or does not return one row, no variables are changed.

\h or\help[command ]

Gives syntax help on the specifiedSQL command. Ifcommand is not specified, thenpsql will list all the commands for which syntax help is available. Ifcommand is an asterisk (*), then syntax help on allSQL 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 or\html

Turns onHTML query output format. If theHTML 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 or\includefilename

Reads input from the filefilename 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 variableECHO toall.

\ir or\include_relativefilename

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[+] [pattern ]

List the databases in the server and show their names, owners, character set encodings, and access privileges. Ifpattern is specified, only databases whose names match the pattern are listed. 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_exportloidfilename

Reads the large object withOIDloid from the database and writes it tofilename. Note that this is subtly different from the server functionlo_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'sOID.

\lo_importfilename [comment ]

Stores the file into aPostgreSQL 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-sidelo_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 allPostgreSQL large objects currently stored in the database, along with any comments provided for them.

\lo_unlinkloid

Deletes the large object withOIDloid from the database.

Tip: Use\lo_list to find out the large object'sOID.

\o or\out [filename ]
\o or\out [ |command ]

Arranges to save future query results to the filefilename or pipe future results to the shell commandcommand. If no argument is specified, the query output is 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 or\print

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 anALTER 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 variablename. 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 ofvalue vary depending on the selected option. For some options, omittingvalue causes the option to be toggled or unset, as described under the particular option. If no such behavior is mentioned, then omittingvalue just results in the current setting being displayed.

\pset without any arguments displays the current status of all printing options.

Adjustable printing options are:

border

Thevalue 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. InHTML format, this will translate directly into theborder=... attribute; in the other formats only values 0 (no border), 1 (internal dividing lines), and 2 (table frame) make sense.latex andlatex-longtable also support aborder value of 3 which adds a dividing line between each row.

columns

Sets the target width for thewrapped 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 variableCOLUMNS, or the detected screen width ifCOLUMNS is not set. In addition, ifcolumns is zero then thewrapped format only affects screen output. Ifcolumns is nonzero then file and pipe output is wrapped to that width as well.

expanded (orx)

Ifvalue is specified it must be eitheron oroff, which will enable or disable expanded mode, orauto. Ifvalue 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

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

format

Sets the output format to one ofunaligned,aligned,wrapped,html,latex (usestabular),latex-longtable, ortroff-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 likealigned 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 thecolumns option. Note thatpsql will not attempt to wrap column header titles; therefore,wrapped format behaves the same asaligned if the total width needed for column headers exceeds the target.

Thehtml,latex,latex-longtable, andtroff-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 necessary inHTML, but inLaTeX you must have a complete document wrapper.latex-longtable also requires theLaTeXlongtable andbooktabs packages.

linestyle

Sets the border line drawing style to one ofascii,old-ascii orunicode. Unique abbreviations are allowed. (That would mean one letter is enough.) The default setting isascii. This option only affects thealigned andwrapped output formats.

ascii style uses plainASCII characters. Newlines in data are shown using a+ symbol in the right-hand margin. When thewrapped 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.

old-ascii style uses plainASCII characters, using the formatting style used inPostgreSQL 8.4 and earlier. Newlines in data are shown using a: symbol in place of the left-hand column separator. When the data is wrapped from one line to the next without a newline character, a; symbol is used in place of the left-hand column separator.

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 theborder setting is greater than zero, this option also determines the characters with which the border lines are drawn. PlainASCII 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

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

pager

Controls use of a pager program for query andpsql help output. If the environment variablePAGER is set, the output is piped to the specified program. Otherwise a platform-dependent default (such asmore) is used.

When thepager option isoff, the pager program is not used. When thepager option ison, the pager is used when appropriate, i.e., when the output is to a terminal and will not fit on the screen. Thepager option can also be set toalways, which causes the pager to be used for all terminal output regardless of whether it fits on the screen.\pset pager without avalue 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 (orT)

InHTML format, this specifies attributes to be placed inside thetable tag. This could for example becellpadding orbgcolor. Note that you probably don't want to specifyborder here, as that is already taken care of by\pset border. If novalue is given, the table attributes are unset.

Inlatex-longtable format, this controls the proportional width of each column containing a left-aligned data type. It is specified as a whitespace-separated list of values, e.g.'0.2 0.2 0.6'. Unspecified output columns use the last specified value.

title

Sets the table title for any subsequently printed tables. This can be used to give your output descriptive tags. If novalue is given, the title is unset.

tuples_only (ort)

Ifvalue is specified it must be eitheron oroff which will enable or disable tuples-only mode. Ifvalue 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 theExamples section.

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

\q or\quit

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

\qechotext [ ... ]

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

\r or\reset

Resets (clears) the query buffer.

\s [filename ]

Printpsql's command line history tofilename. Iffilename is omitted, the history is written to the standard output (using the pager if appropriate). This command is not available ifpsql was built withoutReadline support.

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

Sets thepsql variablename tovalue, 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-setpsql variables.

Valid variable names can contain letters, digits, and underscores. See the sectionVariables 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 theSQL commandSET.

\setenvname [value ]

Sets the environment variablename tovalue, or if thevalue is not supplied, unsets the environment variable. Example:

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

\sf[+]function_description

This command fetches and shows the definition of the named function, in the form of aCREATE 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 examplefoo(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.

\Ttable_options

Specifies attributes to be placed within thetable tag inHTML output format. This command is equivalent to\pset tableattrtable_options.

\timing [on |off ]

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

\unsetname

Unsets (deletes) thepsql variablename.

\w or\writefilename
\w or\write|command

Outputs the current query buffer to the filefilename or pipes it to the shell commandcommand.

\watch [seconds ]

Repeatedly execute the current query buffer (like\g) until interrupted or the query fails. Wait the specified number of seconds (default 2) between executions.

\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 apattern 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 shell or executes the shell commandcommand. The arguments are not further interpreted; the shell will see them as-is. In particular, the variable substitution rules and backslash escapes do not apply.

\?

Shows help information about the backslash commands.

Patterns

The various\d commands accept apattern 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 namedfoo. 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 namedFOO"BAR (notfoo"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 namedfooFOObar.

Whenever thepattern 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 bevisible 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 withint. 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 includesbar that are in schemas whose schema name starts withfoo. 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 inSection 9.7.3, 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+|) forR*, or(R|) forR?.$ 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).

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 thepsql meta-command\set. For example,

testdb=>\set foo bar

sets the variablefoo to the valuebar. To retrieve the content of the variable, precede the name with a colon, for example:

testdb=>\echo :foobar

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

A number of these variables are treated specially bypsql. 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 ofpsql. 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.

SQL Interpolation

A key feature ofpsql variables is that you can substitute ("interpolate") them into regularSQL 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 tablemy_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 quotedSQL 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 ifmy_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 standardSQL for embedded query languages, such asECPG. The colon syntaxes for array slices and type casts arePostgreSQL 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 apsql extension.

Prompting

The promptspsql issues can be customized to your preference. The three variablesPROMPT1,PROMPT2, andPROMPT3 contain strings and special escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued whenpsql 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 anSQLCOPY 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:

To insert a percent sign into your prompt, write%%. The default prompts are'%/%R%# ' for prompts 1 and 2, and'>> ' for prompt 3.

Command-Line Editing

psql supports theReadline library for convenient line editing and retrieval. The command history is automatically saved whenpsql exits and is reloaded whenpsql starts up. Tab-completion is also supported, although the completion logic makes no claim to be anSQL parser. The queries generated by tab-completion can also interfere with other SQL commands, e.g.SET TRANSACTION ISOLATION LEVEL. 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:

$if psqlset disable-completion on$endif

(This is not apsql but aReadline feature. Read its documentation for further details.)