NAME
psql - PostgreSQL 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 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.
-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, it is treated as a
conninfo string. See 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 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.
-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
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 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
--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).
-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 (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 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 in the documentation.) It is also convenient to have a ~/.pgpass
file to avoid regularly having to type in passwords. See in the
documentation for more information.
An alternative way to specify connection parameters is in a conninfo
string, 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"
This way you can also use LDAP for connection parameter lookup as
described in in the documentation. See 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.
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 (8.4.4)
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 [listen(7)] and NOTIFY
[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 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 can quote it with a single
quote. To include a single quote into such an argument, use two single
quotes. 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 ] [ host ] [ port ] ]
Establishes a new connection to a PostgreSQL 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.
\copy { table [ ( column_list ) ] | ( query ) }
Performs a frontend (client) copy. This is an operation that
runs an SQL COPY [copy(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 SQL COPY
[copy(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 SQL COPY 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 PostgreSQL.
\d[S+] [ 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.
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 \dtvs which will show a list of all tables, views, and
sequences. This is purely a convenience measure.
\da[S] [ pattern ]
Lists all available 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 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[S] [ pattern ]
Lists all available 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.
\dC [ pattern ]
Lists all available type casts. If pattern is specified, only
casts whose source or target types match the pattern are listed.
\dd[S] [ 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. By default,
only user-created objects are shown; supply a pattern or the S
modifier to include system objects. ‘‘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
[comment(7)] SQL command.
\dD[S] [ pattern ]
Lists all available domains. If pattern is specified, only
matching domains are shown. By default, only user-created
objects are shown; supply a pattern or the S modifier to include
system objects.
\des[+] [ pattern ]
Lists all 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 desription
of each server is shown, including the server’s ACL, type,
version, and options.
\deu[+] [ pattern ]
Lists all 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 all 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 and options of the foreign-data wrapper
are also shown.
\df[antwS+] [ pattern ]
Lists available functions, together with their arguments, return
types, and their function types: ’agg’ (aggregate), ’normal’,
’trigger’, and ’window’. To display only functions of a specific
type, use the corresponding letters a, n, t, or w. 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.
Note: 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 available 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 available 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 available 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 available 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 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). If the form \dg+ is used,
additional information is shown about each role, including the
comment for each role.
\di[S+] [ pattern ]
\ds[S+] [ pattern ]
\dt[S+] [ pattern ]
\dv[S+] [ pattern ]
In this group of commands, the letters i, s, t, and v stand for
index, sequence, table, and view, respectively. You can specify
any or all of these letters, in any order, to obtain a listing
of all the matching objects. 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. By default, only user-created objects are
shown; supply a pattern or the S modifier to include system
objects.
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 ]
Lists 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[S] [ pattern ]
Lists available 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.
\dp [ pattern ]
Lists 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 GRANT [grant(7)] and REVOKE [revoke(7)] commands are used to
set access privileges.
\dT[S+] [ pattern ]
Lists available 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, as well as its allowed values if it is an enum type. By
default, only user-created objects are shown; supply a pattern
or the S modifier to include system objects.
\du[+] [ pattern ]
Lists all database roles. 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,
including the comment for each role.
\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.
\ef [ function_description ]
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 \e. 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.
\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.
\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, 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 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 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
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.
\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 set variable name. An optional prompt, text,
can be specified. (For multi-word prompts, use single-quotes.)
By default, \prompt uses the terminal for input and output.
However, if the -f command line switch is used, \prompt uses
standard input and 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,
wrapped, 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.
‘‘Wrapped’’ is like aligned but wraps output to the
specified width. If \pset columns is zero (the default),
wrapped mode only affects screen output and wrapped width
is controlled by the environment variable COLUMNS or the
detected screen width. If \pset columns is set to a non-
zero value, all output is wrapped, including file and
pipe output.
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.)
columns
Controls the target width for the wrapped format, and
width for determining if wide output requires the pager.
Zero (the default) causes the wrapped format to affect
only screen output.
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)
You can specify an optional second argument, if it is
provided it may be either on or off which will enable or
disable expanded mode. If the second argument is not
provided then we will toggle 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 You can specify an optional second argument, if it is
provided it may be either on or off which will enable or
disable display of the default footer (x rows). If the
second argument is not provided then we will toggle
between on and off.
numericlocale
You can specify an optional second argument, if it is
provided it may be either on or off which will enable or
disable display of a locale-aware character to separate
groups of digits to the left of the decimal marker. If
the second argument is not provided then we will toggle
between on and off.
recordsep
Specifies the record (line) separator to use in unaligned
output mode. The default is a newline character.
tuples_only (or t)
You can specify an optional second argument, if it is
provided it may be either on or off which will enable or
disable the tuples only mode. If the second argument is
not provided then we will toggle between tuples only and
full display. Full display shows 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. \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 [psql(1)] 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 [psql(1)] 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
[set(7)].
\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 [ on | off ]
Without parameter, toggles a display of how long each SQL
statement takes, in milliseconds. With parameter, sets same.
\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 \pset expanded.
\z [ pattern ]
Produces a list of all available 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.
The GRANT [grant(7)] and REVOKE [revoke(7)] commands are used to
set access privileges.
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.
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 all 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 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).
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 the pattern *. To see all objects in the
database, use the pattern *.*.
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. To set variables, use the psql meta-
command \set:
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 and use it as the argument of
any slash command:
testdb=> \echo :foo
bar
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.
If you call \set without a second argument, the variable is set, with
an empty string as value. To unset (or delete) a variable, use the
command \unset.
psql’s internal variable names can consist of letters, numbers, and
underscores in any order and any number of them. A number of these
variables are treated specially by psql. They indicate certain option
settings that can be changed at run time by altering the value of the
variable or represent some state of the application. Although you can
use these variables for any other purpose, this is not recommended, as
the program behavior might grow really strange really quickly. By
convention, all specially treated variables consist of all upper-case
letters (and possibly numbers 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 PostgreSQL’s traditional
behavior, 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.
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
PostgreSQL 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_insert 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, if non-interactive scripts encounter an error, such
as a malformed SQL command or internal meta-command, processing
continues. This has been the traditional behavior of psql but it
is sometimes not desirable. If this variable is set, script
processing will immediately terminate. If the script was called
from another script it will terminate in the same fashion. If
the outermost script was not called from an interactive psql
session but rather using the -f option, psql will return error
code 3, to distinguish this case from fatal error conditions
(error code 1).
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 [psql(1)] 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
An additional useful feature of psql variables is that you can
substitute (‘‘interpolate’’) them into regular SQL statements. The
syntax for this is again to prepend the variable name with a colon (:):
testdb=> \set foo ’my_table’
testdb=> SELECT * FROM :foo;
would then query the table my_table. The value of the variable is
copied literally, so it can even contain unbalanced quotes or backslash
commands. You must make sure that it makes sense where you put it.
Variable interpolation will not be performed into quoted SQL entities.
One possible 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
proceed as above:
testdb=> \set content ’’’’ ‘cat my_file.txt‘ ’’’’
testdb=> INSERT INTO my_table VALUES (:content);
One problem with this approach is that my_file.txt might contain single
quotes. These need to be escaped so that they don’t cause a syntax
error when the second line is processed. This could be done with the
program sed:
testdb=> \set content ’’’’ ‘sed -e "s/’/’’/g" < my_file.txt‘ ’’’’
If you are using non-standard-conforming strings then you’ll also need
to double backslashes. This is a bit tricky:
testdb=> \set content ’’’’ ‘sed -e "s/’/’’/g" -e ’s/\\/\\\\/g’ < my_file.txt‘ ’’’’
Note the use of different shell quoting conventions so that neither the
single quote marks nor the backslashes are special to the shell.
Backslashes are still special to sed, however, so we need to double
them. (Perhaps at one point you thought it was great that all Unix
commands use the same escape character.)
Since colons can legally appear in SQL commands, the following rule
applies: the character sequence ‘‘:name’’ is not changed unless
‘‘name’’ is the name of a variable that 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 syntax for array
slices and type casts are PostgreSQL extensions, hence the conflict.)
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 SQL COPY 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
[psql(1)] 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.
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 in the documentation).
PSQL_EDITOR
EDITOR
VISUAL Editor used by the \e command. The variables are examined in the
order listed; the first that is set is used.
SHELL Command executed by the \! command.
TMPDIR Directory for storing temporary files. The default is /tmp.
This utility, like most other PostgreSQL utilities, also uses the
environment variables supported by libpq (see in the documentation).
FILES
· Before starting up, psql attempts to read and execute commands from
the system-wide psqlrc file and the user’s ~/.psqlrc file. (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).
· Both the system-wide psqlrc file and the user’s ~/.psqlrc file can be
made version-specific by appending a dash and the PostgreSQL release
number, for example ~/.psqlrc-8.4.4. A matching version-specific
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.
NOTES
· In an earlier life psql allowed the first argument of a single-letter
backslash command to start directly after the command, without
intervening whitespace. As of PostgreSQL 8.4 this is no longer
allowed.
· 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 with servers of versions back to 7.4, though not
necessarily with servers newer than psql itself.
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