Provided by: postgresql-client-9.3_9.3.24-0ubuntu0.14.04_amd64 
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 nonempty input lines to standard output as they are read. (This does not
apply to lines read interactively.) This is equivalent to setting the variable ECHO to
all.
-A, --no-align
Switches to unaligned output mode. (The default output mode is otherwise aligned.)
-c command, --command=command
Specifies that psql is to execute one command string, command, and then exit. This is
useful in shell scripts. Start-up files (psqlrc and ~/.psqlrc) are ignored with this
option.
command must be either a command string that is completely parsable by the server
(i.e., it contains no psql-specific features), or a single backslash command. Thus you
cannot mix SQL and psql meta-commands with this option. To achieve that, you could
pipe the string into psql, for example: echo '\x \\ SELECT * FROM foo;' | psql. (\\ is
the separator meta-command.)
If the command string contains multiple SQL commands, they are processed in a single
transaction, unless there are explicit BEGIN/COMMIT commands included in the string to
divide it into multiple transactions. This is different from the behavior when the
same string is fed to psql's standard input. Also, only the result of the last SQL
command is returned.
Because of these legacy behaviors, putting more than one command in the -c string
often has unexpected results. It's better to feed multiple commands to psql's standard
input, either using echo as illustrated above, or via a shell here-document, for
example:
psql <<EOF
\x
SELECT * FROM foo;
EOF
-d dbname, --dbname=dbname
Specifies the name of the database to connect to. This is equivalent to specifying
dbname as the first non-option argument on the command line.
If this parameter contains an = sign or starts with a valid URI prefix (postgresql://
or postgres://), it is treated as a conninfo string. See Section 31.1.1, “Connection
Strings”, 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 to on.
-f filename, --file=filename
Use the file filename as the source of commands instead of reading commands
interactively. After the file is processed, psql terminates. This is in many ways
equivalent to the meta-command \i.
If filename is - (hyphen), then standard input is read until an EOF indication or \q
meta-command. Note however that Readline is not used in this case (much as if -n had
been specified).
Using this option is subtly different from writing psql < filename. In general, both
will do what you expect, but using -f enables some nice features such as error
messages with line numbers. There is also a slight chance that using this option will
reduce the start-up overhead. On the other hand, the variant using the shell's input
redirection is (in theory) guaranteed to yield exactly the same output you would have
received had you entered everything by hand.
-F separator, --field-separator=separator
Use separator as the field separator for unaligned output. This is equivalent to \pset
fieldsep or \f.
-h hostname, --host=hostname
Specifies the host name of the machine on which the server is running. If the value
begins with a slash, it is used as the directory for the Unix-domain socket.
-H, --html
Turn on HTML tabular output. This is equivalent to \pset format html or the \H
command.
-l, --list
List all available databases, then exit. Other non-connection options are ignored.
This is similar to the meta-command \list.
-L filename, --log-file=filename
Write all query output into file filename, in addition to the normal output
destination.
-n, --no-readline
Do not use Readline for line editing and do not use the command history. This can be
useful to turn off tab expansion when cutting and pasting.
-o filename, --output=filename
Put all query output into file filename. This is equivalent to the command \o.
-p port, --port=port
Specifies the TCP port or the local Unix-domain socket file extension on which the
server is listening for connections. Defaults to the value of the PGPORT environment
variable or, if not set, to the port specified at compile time, usually 5432.
-P assignment, --pset=assignment
Specifies printing options, in the style of \pset. Note that here you have to separate
name and value with an equal sign instead of a space. For example, to set the output
format to LaTeX, you could write -P format=latex.
-q, --quiet
Specifies that psql should do its work quietly. By default, it prints welcome messages
and various informational output. If this option is used, none of this happens. This
is useful with the -c option. This is equivalent to setting the variable QUIET to on.
-R separator, --record-separator=separator
Use separator as the record separator for unaligned output. This is equivalent to the
\pset recordsep command.
-s, --single-step
Run in single-step mode. That means the user is prompted before each command is sent
to the server, with the option to cancel execution as well. Use this to debug scripts.
-S, --single-line
Runs in single-line mode where a newline terminates an SQL command, as a semicolon
does.
Note
This mode is provided for those who insist on it, but you are not necessarily
encouraged to use it. In particular, if you mix SQL and meta-commands on a line
the order of execution might not always be clear to the inexperienced user.
-t, --tuples-only
Turn off printing of column names and result row count footers, etc. This is
equivalent to the \t command.
-T table_options, --table-attr=table_options
Specifies options to be placed within the 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 meta-command. Note that you must separate
name and value, if any, by an equal sign on the command line. To unset a variable,
leave off the equal sign. To set a variable with an empty value, use the equal sign
but leave off the value. These assignments are done during a very early stage of
start-up, so variables reserved for internal purposes might get overwritten later.
-V, --version
Print the psql version and exit.
-w, --no-password
Never issue a password prompt. If the server requires password authentication and a
password is not available by other means such as a .pgpass file, the connection
attempt will fail. This option can be useful in batch jobs and scripts where no user
is present to enter a password.
Note that this option will remain set for the entire session, and so it affects uses
of the meta-command \connect as well as the initial connection attempt.
-W, --password
Force psql to prompt for a password before connecting to a database.
This option is never essential, since psql will automatically prompt for a password if
the server demands password authentication. However, psql will waste a connection
attempt finding out that the server wants a password. In some cases it is worth typing
-W to avoid the extra connection attempt.
Note that this option will remain set for the entire session, and so it affects uses
of the meta-command \connect as well as the initial connection attempt.
-x, --expanded
Turn on the expanded table formatting mode. This is equivalent to the \x command.
-X,, --no-psqlrc
Do not read the start-up file (neither the system-wide psqlrc file nor the user's
~/.psqlrc file).
-z, --field-separator-zero
Set the field separator for unaligned output to a zero byte.
-0, --record-separator-zero
Set the record separator for unaligned output to a zero byte. This is useful for
interfacing, for example, with xargs -0.
-1, --single-transaction
When psql executes a script, adding this option wraps BEGIN/COMMIT around the script
to execute it as a single transaction. This ensures that either all the commands
complete successfully, or no changes are applied.
If the script itself uses BEGIN, COMMIT, or ROLLBACK, this option will not have the
desired effects. Also, if the script contains any command that cannot be executed
inside a transaction block, specifying this option will cause that command (and hence
the whole transaction) to fail.
-?, --help
Show help about psql command line arguments, and exit.
EXIT STATUS
psql returns 0 to the shell if it finished normally, 1 if a fatal error of its own occurs
(e.g. out of memory, file not found), 2 if the connection to the server went bad and the
session was not interactive, and 3 if an error occurred in a script and the variable
ON_ERROR_STOP was set.
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 of these
options are required; there are useful defaults. If you omit the host name, psql will
connect via a Unix-domain socket to a server on the local host, or via TCP/IP to localhost
on machines that don't have Unix-domain sockets. The default port number is determined at
compile time. Since the database server uses the same default, you will not have to
specify the port in most cases. The default user name is your operating-system user name,
as is the default database name. Note that you cannot just connect to any database under
any user name. Your database administrator should have informed you about your access
rights.
When the defaults aren't quite right, you can save yourself some typing by setting the
environment variables PGDATABASE, PGHOST, PGPORT and/or PGUSER to appropriate values. (For
additional environment variables, see Section 31.14, “Environment Variables”, in the
documentation.) It is also convenient to have a ~/.pgpass file to avoid regularly having
to type in passwords. See Section 31.15, “The Password File”, in the documentation for
more information.
An alternative way to specify connection parameters is in a conninfo string or a URI,
which is used instead of a database name. This mechanism give you very wide control over
the connection. For example:
$ psql "service=myservice sslmode=require"
$ psql postgresql://dbmaster:5433/mydb?sslmode=require
This way you can also use LDAP for connection parameter lookup as described in Section
31.17, “LDAP Lookup of Connection Parameters”, in the documentation. See Section 31.1.2,
“Parameter Key Words”, in the documentation for more information on all the available
connection options.
If the connection could not be made for any reason (e.g., insufficient privileges, server
is not running on the targeted host, etc.), psql will return an error and terminate.
If both standard input and standard output are a terminal, then psql sets the client
encoding to “auto”, which will detect the appropriate client encoding from the locale
settings (LC_CTYPE environment variable on Unix systems). If this doesn't work out as
expected, the client encoding can be overridden using the environment variable
PGCLIENTENCODING.
Entering SQL Commands
In normal operation, psql provides a prompt with the name of the database to which psql is
currently connected, followed by the string =>. For example:
$ psql testdb
psql (9.3.24)
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.
If untrusted users have access to a database that has not adopted a secure schema usage
pattern, begin your session by removing publicly-writable schemas from search_path. One
can add options=-csearch_path= to the connection string or issue SELECT
pg_catalog.set_config('search_path', '', false) before other SQL commands. This
consideration is not specific to psql; it applies to every interface for executing
arbitrary SQL commands.
Whenever a command is executed, psql also polls for asynchronous notification events
generated by LISTEN(7) and NOTIFY(7).
Meta-Commands
Anything you enter in psql that begins with an unquoted backslash is a psql meta-command
that is processed by psql itself. These commands make psql more useful for administration
or scripting. Meta-commands are often called slash or backslash commands.
The format of a psql command is the backslash, followed immediately by a command verb,
then any arguments. The arguments are separated from the command verb and each other by
any number of whitespace characters.
To include whitespace in an argument you can quote it with single quotes. To include a
single quote in an argument, write two single quotes within single-quoted text. Anything
contained in single quotes is furthermore subject to C-like substitutions for \n (new
line), \t (tab), \b (backspace), \r (carriage return), \f (form feed), \digits (octal),
and \xdigits (hexadecimal). A backslash preceding any other character within single-quoted
text quotes that single character, whatever it is.
Within an argument, text that is enclosed in backquotes (`) is taken as a command line
that is passed to the shell. The output of the command (with any trailing newline removed)
replaces the backquoted text.
If an unquoted colon (:) followed by a psql variable name appears within an argument, it
is replaced by the variable's value, as described in SQL Interpolation.
Some commands take an SQL identifier (such as a table name) as argument. These arguments
follow the syntax rules of SQL: Unquoted letters are forced to lowercase, while double
quotes (") protect letters from case conversion and allow incorporation of whitespace into
the identifier. Within double quotes, paired double quotes reduce to a single double quote
in the resulting name. For example, FOO"BAR"BAZ is interpreted as fooBARbaz, and "A
weird"" name" becomes A weird" name.
Parsing for arguments stops at the end of the line, or when another unquoted backslash is
found. An unquoted backslash is taken as the beginning of a new meta-command. The special
sequence \\ (two backslashes) marks the end of arguments and continues parsing SQL
commands, if any. That way SQL and psql commands can be freely mixed on a line. But in any
case, the arguments of a meta-command cannot continue beyond the end of the line.
The following meta-commands are defined:
\a
If the current table output format is unaligned, it is switched to aligned. If it is
not unaligned, it is set to unaligned. This command is kept for backwards
compatibility. See \pset for a more general solution.
\c or \connect [ -reuse-previous=on|off ] [ dbname [ username ] [ host ] [ port ] |
conninfo ]
Establishes a new connection to a PostgreSQL server. The connection parameters to use
can be specified either using a positional syntax, or using conninfo connection
strings as detailed in Section 31.1.1, “Connection Strings”, in the documentation.
Where the command omits database name, user, host, or port, the new connection can
reuse values from the previous connection. By default, values from the previous
connection are reused except when processing a conninfo string. Passing a first
argument of -reuse-previous=on or -reuse-previous=off overrides that default. When the
command neither specifies nor reuses a particular parameter, the libpq default is
used. Specifying any of dbname, username, host or port as - is equivalent to omitting
that parameter.
If the new connection is successfully made, the previous connection is closed. 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.
Examples:
=> \c mydb myuser host.dom 6432
=> \c service=foo
=> \c "host=localhost port=5432 dbname=mydb connect_timeout=10 sslmode=disable"
=> \c postgresql://tom@localhost/mydb?application_name=myapp
\C [ title ]
Sets the title of any tables being printed as the result of a query or unset any such
title. This command is equivalent to \pset title title. (The name of this command
derives from “caption”, as it was previously only used to set the caption in an HTML
table.)
\cd [ directory ]
Changes the current working directory to directory. Without argument, changes to the
current user's home directory.
Tip
To print your current working directory, use \! pwd.
\conninfo
Outputs information about the current database connection.
\copy { table [ ( column_list ) ] | ( query ) } { from | to } { 'filename' | program
'command' | stdin | stdout | pstdin | pstdout } [ [ with ] ( option [, ...] ) ]
Performs a frontend (client) copy. This is an operation that runs an SQL 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.
When program is specified, command is executed by psql and the data from or to command
is routed between the server and the client. This means that the execution privileges
are those of the local user, not the server, and no SQL superuser privileges are
required.
\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.
The syntax of the command is similar to that of the SQL COPY(7) command, and option
must indicate one of the options of the SQL 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.
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, materialized view, index, sequence, or foreign table)
or composite type matching the pattern, show all columns, their types, the tablespace
(if not the default) and any special attributes such as NOT NULL or defaults.
Associated indexes, constraints, rules, and triggers are also shown. For foreign
tables, the associated foreign server is shown as well. (“Matching the pattern” is
defined in Patterns below.)
For some types of relation, \d shows additional information for each column: column
values for sequences, indexed expressions for indexes, and foreign data wrapper
options for foreign tables.
The command form \d+ is identical, except that more information is displayed: any
comments associated with the columns of the table are shown, as is the presence of
OIDs in the table, the view definition if the relation is a view.
By default, only user-created objects are shown; supply a pattern or the S modifier to
include system objects.
Note
If \d is used without a pattern argument, it is equivalent to \dtvmsE which will
show a list of all visible tables, views, materialized views, sequences and
foreign tables. This is purely a convenience measure.
\da[S] [ pattern ]
Lists aggregate functions, together with their return type and the data types they
operate on. If pattern is specified, only aggregates whose names match the pattern are
shown. By default, only user-created objects are shown; supply a pattern or the S
modifier to include system objects.
\db[+] [ pattern ]
Lists tablespaces. If pattern is specified, only tablespaces whose names match the
pattern are shown. If + is appended to the command name, each object is listed with
its associated permissions.
\dc[S+] [ pattern ]
Lists conversions between character-set encodings. If pattern is specified, only
conversions whose names match the pattern are listed. By default, only user-created
objects are shown; supply a pattern or the S modifier to include system objects. If +
is appended to the command name, each object is listed with its associated
description.
\dC[+] [ pattern ]
Lists type casts. If pattern is specified, only casts whose source or target types
match the pattern are listed. If + is appended to the command name, each object is
listed with its associated description.
\dd[S] [ pattern ]
Shows the descriptions of objects of type constraint, operator class, operator family,
rule, and trigger. All other comments may be viewed by the respective backslash
commands for those object types.
\dd displays descriptions for objects matching the pattern, or of visible objects of
the appropriate type if no argument is given. But in either case, only objects that
have a description are listed. By default, only user-created objects are shown; supply
a pattern or the S modifier to include system objects.
Descriptions for objects can be created with the COMMENT(7) SQL command.
\ddp [ pattern ]
Lists default access privilege settings. An entry is shown for each role (and schema,
if applicable) for which the default privilege settings have been changed from the
built-in defaults. If pattern is specified, only entries whose role name or schema
name matches the pattern are listed.
The ALTER DEFAULT PRIVILEGES (ALTER_DEFAULT_PRIVILEGES(7)) command is used to set
default access privileges. The meaning of the privilege display is explained under
GRANT(7).
\dD[S+] [ pattern ]
Lists domains. If pattern is specified, only domains whose names match the pattern are
shown. By default, only user-created objects are shown; supply a pattern or the S
modifier to include system objects. If + is appended to the command name, each object
is listed with its associated permissions and description.
\dE[S+] [ pattern ], \di[S+] [ pattern ], \dm[S+] [ pattern ], \ds[S+] [ pattern ],
\dt[S+] [ pattern ], \dv[S+] [ pattern ]
In this group of commands, the letters E, i, m, s, t, and v 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. If pattern is specified, only objects whose names match the pattern are listed.
By default, only user-created objects are shown; supply a pattern or the S modifier to
include system objects.
\des[+] [ pattern ]
Lists foreign servers (mnemonic: “external servers”). If pattern is specified, only
those servers whose name matches the pattern are listed. If the form \des+ is used, a
full description of each server is shown, including the server's ACL, type, version,
options, and description.
\det[+] [ pattern ]
Lists foreign tables (mnemonic: “external tables”). If pattern is specified, only
entries whose table name or schema name matches the pattern are listed. If the form
\det+ is used, generic options and the foreign table description are also displayed.
\deu[+] [ pattern ]
Lists user mappings (mnemonic: “external users”). If pattern is specified, only those
mappings whose user names match the pattern are listed. If the form \deu+ is used,
additional information about each mapping is shown.
Caution
\deu+ might also display the user name and password of the remote user, so care
should be taken not to disclose them.
\dew[+] [ pattern ]
Lists foreign-data wrappers (mnemonic: “external wrappers”). If pattern is specified,
only those foreign-data wrappers whose name matches the pattern are listed. If the
form \dew+ is used, the ACL, options, and description of the foreign-data wrapper are
also shown.
\df[antwS+] [ pattern ]
Lists functions, together with their arguments, return types, and function types,
which are classified as “agg” (aggregate), “normal”, “trigger”, or “window”. To
display only functions of specific type(s), add the corresponding letters a, n, t, or
w to the command. If pattern is specified, only functions whose names match the
pattern are shown. If the form \df+ is used, additional information about each
function, including security, volatility, language, source code and description, is
shown. By default, only user-created objects are shown; supply a pattern or the S
modifier to include system objects.
Tip
To look up functions taking arguments or returning values of a specific type, use
your pager's search capability to scroll through the \df output.
\dF[+] [ pattern ]
Lists text search configurations. If pattern is specified, only configurations whose
names match the pattern are shown. If the form \dF+ is used, a full description of
each configuration is shown, including the underlying text search parser and the
dictionary list for each parser token type.
\dFd[+] [ pattern ]
Lists text search dictionaries. If pattern is specified, only dictionaries whose names
match the pattern are shown. If the form \dFd+ is used, additional information is
shown about each selected dictionary, including the underlying text search template
and the option values.
\dFp[+] [ pattern ]
Lists text search parsers. If pattern is specified, only parsers whose names match the
pattern are shown. If the form \dFp+ is used, a full description of each parser is
shown, including the underlying functions and the list of recognized token types.
\dFt[+] [ pattern ]
Lists text search templates. If pattern is specified, only templates whose names match
the pattern are shown. If the form \dFt+ is used, additional information is shown
about each template, including the underlying function names.
\dg[+] [ pattern ]
Lists database roles. (Since the concepts of “users” and “groups” have been unified
into “roles”, this command is now equivalent to \du.) If pattern is specified, only
those roles whose names match the pattern are listed. If the form \dg+ is used,
additional information is shown about each role; currently this adds the comment for
each role.
\dl
This is an alias for \lo_list, which shows a list of large objects.
\dL[S+] [ pattern ]
Lists procedural languages. If pattern is specified, only languages whose names match
the pattern are listed. By default, only user-created languages are shown; supply the
S modifier to include system objects. If + is appended to the command name, each
language is listed with its call handler, validator, access privileges, and whether it
is a system object.
\dn[S+] [ pattern ]
Lists schemas (namespaces). If pattern is specified, only schemas whose names match
the pattern are listed. By default, only user-created objects are shown; supply a
pattern or the S modifier to include system objects. If + is appended to the command
name, each object is listed with its associated permissions and description, if any.
\do[S] [ pattern ]
Lists operators with their operand and return types. If pattern is specified, only
operators whose names match the pattern are listed. By default, only user-created
objects are shown; supply a pattern or the S modifier to include system objects.
\dO[S+] [ pattern ]
Lists collations. If pattern is specified, only collations whose names match the
pattern are listed. By default, only user-created objects are shown; supply a pattern
or the S modifier to include system objects. If + is appended to the command name,
each collation is listed with its associated description, if any. Note that only
collations usable with the current database's encoding are shown, so the results may
vary in different databases of the same installation.
\dp [ pattern ]
Lists tables, views and sequences with their associated access privileges. If pattern
is specified, only tables, views and sequences whose names match the pattern are
listed.
The GRANT(7) and REVOKE(7) commands are used to set access privileges. The meaning of
the privilege display is explained under GRANT(7).
\drds [ role-pattern [ database-pattern ] ]
Lists defined configuration settings. These settings can be role-specific,
database-specific, or both. role-pattern and database-pattern are used to select
specific roles and databases to list, respectively. If omitted, or if * is specified,
all settings are listed, including those not role-specific or database-specific,
respectively.
The ALTER ROLE (ALTER_ROLE(7)) and ALTER DATABASE (ALTER_DATABASE(7)) commands are
used to define per-role and per-database configuration settings.
\dT[S+] [ pattern ]
Lists data types. If pattern is specified, only types whose names match the pattern
are listed. If + is appended to the command name, each type is listed with its
internal name and size, its allowed values if it is an enum type, and its associated
permissions. By default, only user-created objects are shown; supply a pattern or the
S modifier to include system objects.
\du[+] [ pattern ]
Lists database roles. (Since the concepts of “users” and “groups” have been unified
into “roles”, this command is now equivalent to \dg.) If pattern is specified, only
those roles whose names match the pattern are listed. If the form \du+ is used,
additional information is shown about each role; currently this adds the comment for
each role.
\dx[+] [ pattern ]
Lists installed extensions. If pattern is specified, only those extensions whose names
match the pattern are listed. If the form \dx+ is used, all the objects belonging to
each matching extension are listed.
\dy[+] [ pattern ]
Lists event triggers. If pattern 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 ]
If filename is specified, the file is edited; after the editor exits, its content is
copied back to the query buffer. If no filename is given, the current query buffer is
copied to a temporary file which is then edited in the same fashion.
The new query buffer is then re-parsed according to the normal rules of psql, where
the whole buffer is treated as a single line. (Thus you cannot make scripts this way.
Use \i for that.) This means that if the query ends with (or contains) a semicolon, it
is immediately executed. Otherwise it will merely wait in the query buffer; type
semicolon or \g to send it, or \r to cancel.
If a line number is specified, psql will position the cursor on the specified line of
the file or query buffer. Note that if a single all-digits argument is given, psql
assumes it is a line number, not a file name.
Tip
See under ENVIRONMENT for how to configure and customize your editor.
\echo text [ ... ]
Prints the arguments to the standard output, separated by one space and followed by a
newline. This can be useful to intersperse information in the output of scripts. For
example:
=> \echo `date`
Tue Oct 26 21:40:57 CEST 1999
If the first argument is an unquoted -n the trailing newline is not written.
Tip
If you use the \o command to redirect your query output you might wish to use
\qecho instead of this command.
\ef [ function_description [ line_number ] ]
This command fetches and edits the definition of the named function, in the form of a
CREATE OR REPLACE FUNCTION command. Editing is done in the same way as for \edit.
After the editor exits, the updated command waits in the query buffer; type semicolon
or \g to send it, or \r to cancel.
The target function can be specified by name alone, or by name and arguments, for
example foo(integer, text). The argument types must be given if there is more than one
function of the same name.
If no function is specified, a blank CREATE FUNCTION template is presented for
editing.
If a line number is specified, psql will position the cursor on the specified line of
the function body. (Note that the function body typically does not begin on the first
line of the file.)
Tip
See under ENVIRONMENT for how to configure and customize your editor.
\encoding [ encoding ]
Sets the client character set encoding. Without an argument, this command shows the
current encoding.
\f [ string ]
Sets the field separator for unaligned query output. The default is the vertical bar
(|). See also \pset for a generic way of setting output options.
\g [ filename ], \g [ |command ]
Sends the current query input buffer to the server, and optionally stores the query's
output in filename or pipes the output to the shell command command. 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 into
psql variables (see Variables). 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 :var2
hello 10
If you specify a prefix, 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_var2
hello 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 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 or \html
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 or \include filename
Reads input from the file filename and executes it as though it had been typed on the
keyboard.
If filename is - (hyphen), then standard input is read until an EOF indication or \q
meta-command. This can be used to intersperse interactive input with input from files.
Note that Readline behavior will be used only if it is active at the outermost level.
Note
If you want to see the lines on the screen as they are read you must set the
variable ECHO to all.
\ir or \include_relative filename
The \ir command is similar to \i, but resolves relative file names differently. When
executing in interactive mode, the two commands behave identically. However, when
invoked from a script, \ir interprets file names relative to the directory in which
the script is located, rather than the current working directory.
\l[+] or \list[+] [ pattern ]
List the databases in the server and show their names, owners, character set
encodings, and access privileges. If pattern 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_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 or \out [ filename ], \o or \out [ |command ]
Arranges to save future query results to the file filename or pipe future results to
the shell command command. 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 an
ALTER ROLE command. This makes sure that the new password does not appear in cleartext
in the command history, the server log, or elsewhere.
\prompt [ text ] name
Prompts the user to supply text, which is assigned to the variable name. An optional
prompt string, text, can be specified. (For multiword prompts, surround the text with
single quotes.)
By default, \prompt uses the terminal for input and output. However, if the -f command
line switch was used, \prompt uses standard input and standard output.
\pset option [ value ]
This command sets options affecting the output of query result tables. option
indicates which option is to be set. The semantics of value vary depending on the
selected option. For some options, omitting value causes the option to be toggled or
unset, as described under the particular option. If no such behavior is mentioned,
then omitting value just results in the current setting being displayed.
Adjustable printing options are:
border
The value must be a number. In general, the higher the number the more borders and
lines the tables will have, but this depends on the particular format. In HTML
format, this will translate directly into the border=... attribute; in the other
formats only values 0 (no border), 1 (internal dividing lines), and 2 (table
frame) make sense. latex and latex-longtable also support a border value of 3
which adds a dividing line between each row.
columns
Sets the target width for the wrapped format, and also the width limit for
determining whether output is wide enough to require the pager or switch to the
vertical display in expanded auto mode. Zero (the default) causes the target width
to be controlled by the environment variable COLUMNS, or the detected screen width
if COLUMNS is not set. In addition, if columns is zero then the wrapped format
only affects screen output. If columns is nonzero then file and pipe output is
wrapped to that width as well.
expanded (or x)
If value is specified it must be either on or off, which will enable or disable
expanded mode, or auto. If value is omitted the command toggles between the on and
off settings. When expanded mode is enabled, query results are displayed in two
columns, with the column name on the left and the data on the right. This mode is
useful if the data wouldn't fit on the screen in the normal “horizontal” mode. In
the auto setting, the expanded mode is used whenever the query output is wider
than the screen, otherwise the regular mode is used. The auto setting is only
effective in the aligned and wrapped formats. In other formats, it always behaves
as if the expanded mode is off.
fieldsep
Specifies the field separator to be used in unaligned output format. That way one
can create, for example, tab- or comma-separated output, which other programs
might prefer. To set a tab as field separator, type \pset fieldsep '\t'. The
default field separator is '|' (a vertical bar).
fieldsep_zero
Sets the field separator to use in unaligned output format to a zero byte.
footer
If value is specified it must be either on or off which will enable or disable
display of the table footer (the (n rows) count). If value is omitted the command
toggles footer display on or off.
format
Sets the output format to one of unaligned, aligned, wrapped, html, latex (uses
tabular), latex-longtable, or troff-ms. Unique abbreviations are allowed. (That
would mean one letter is enough.)
unaligned format writes all columns of a row on one line, separated by the
currently active field separator. This is useful for creating output that might be
intended to be read in by other programs (for example, tab-separated or
comma-separated format).
aligned format is the standard, human-readable, nicely formatted text output; this
is the default.
wrapped format is like aligned but wraps wide data values across lines to make the
output fit in the target column width. The target width is determined as described
under the columns option. Note that psql will not attempt to wrap column header
titles; therefore, wrapped format behaves the same as aligned if the total width
needed for column headers exceeds the target.
The html, latex, latex-longtable, and troff-ms formats put out tables that are
intended to be included in documents using the respective mark-up language. They
are not complete documents! This might not be necessary in HTML, but in LaTeX you
must have a complete document wrapper. latex-longtable also requires the LaTeX
longtable and booktabs packages.
linestyle
Sets the border line drawing style to one of ascii, old-ascii or unicode. Unique
abbreviations are allowed. (That would mean one letter is enough.) The default
setting is ascii. This option only affects the aligned and wrapped output formats.
ascii style uses plain ASCII characters. Newlines in data are shown using a +
symbol in the right-hand margin. When the wrapped format wraps data from one line
to the next without a newline character, a dot (.) is shown in the right-hand
margin of the first line, and again in the left-hand margin of the following line.
old-ascii style uses plain ASCII characters, using the formatting style used in
PostgreSQL 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 the border setting is greater than zero, this option also determines the
characters with which the border lines are drawn. Plain ASCII characters work
everywhere, but Unicode characters look nicer on displays that recognize them.
null
Sets the string to be printed in place of a null value. The default is to print
nothing, which can easily be mistaken for an empty string. For example, one might
prefer \pset null '(null)'.
numericlocale
If value is specified it must be either on or off which will enable or disable
display of a locale-specific character to separate groups of digits to the left of
the decimal marker. If value is omitted the command toggles between regular and
locale-specific numeric output.
pager
Controls use of a pager program for query and psql help output. If the environment
variable PAGER is set, the output is piped to the specified program. Otherwise a
platform-dependent default (such as more) is used.
When the pager option is off, the pager program is not used. When the pager option
is on, the pager is used when appropriate, i.e., when the output is to a terminal
and will not fit on the screen. The pager option can also be set to always, which
causes the pager to be used for all terminal output regardless of whether it fits
on the screen. \pset pager without a value toggles pager use on and off.
recordsep
Specifies the record (line) separator to use in unaligned output format. The
default is a newline character.
recordsep_zero
Sets the record separator to use in unaligned output format to a zero byte.
tableattr (or T)
In HTML format, this specifies attributes to be placed inside the 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. If no value
is given, the table attributes are unset.
In latex-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 no value is given, the title is unset.
tuples_only (or t)
If value is specified it must be either on or off which will enable or disable
tuples-only mode. If value is omitted the command toggles between regular and
tuples-only output. Regular output includes extra information such as column
headers, titles, and various footers. In tuples-only mode, only actual table data
is shown.
Illustrations of how these different formats look can be seen in the EXAMPLES section.
Tip
There are various shortcut commands for \pset. See \a, \C, \f, \H, \t, \T, and \x.
Note
It is an error to call \pset without any arguments. In the future this case might
show the current status of all printing options.
\q or \quit
Quits the psql program. In a script file, only execution of that script is terminated.
\qecho text [ ... ]
This command is identical to \echo except that the output will be written to the query
output channel, as set by \o.
\r or \reset
Resets (clears) the query buffer.
\s [ filename ]
Print psql's command line history to filename. If filename is omitted, the history is
written to the standard output (using the pager if appropriate). This command is not
available if psql was built without Readline support.
\set [ name [ value [ ... ] ] ]
Sets the psql variable name to value, or if more than one value is given, to the
concatenation of all of them. If only one argument is given, the variable is set with
an empty value. To unset a variable, use the \unset command.
\set without any arguments displays the names and values of all currently-set psql
variables.
Valid variable names can contain letters, digits, and underscores. See the section
Variables below for details. Variable names are case-sensitive.
Although you are welcome to set any variable to anything you want, psql treats several
variables as special. They are documented in the section about variables.
Note
This command is unrelated to the SQL command SET(7).
\setenv name [ value ]
Sets the environment variable name to value, or if the value is not supplied, unsets
the environment variable. Example:
testdb=> \setenv PAGER less
testdb=> \setenv LESS -imx4F
\sf[+] function_description
This command fetches and shows the definition of the named function, in the form of a
CREATE OR REPLACE FUNCTION command. The definition is printed to the current query
output channel, as set by \o.
The target function can be specified by name alone, or by name and arguments, for
example foo(integer, text). The argument types must be given if there is more than one
function of the same name.
If + is appended to the command name, then the output lines are numbered, with the
first line of the function body being line 1.
\t
Toggles the display of output column name headings and row count footer. This command
is equivalent to \pset tuples_only and is provided for convenience.
\T table_options
Specifies attributes to be placed within the table tag in HTML output format. This
command is equivalent to \pset tableattr table_options.
\timing [ on | off ]
Without parameter, toggles a display of how long each SQL statement takes, in
milliseconds. With parameter, sets same.
\unset name
Unsets (deletes) the psql variable name.
\w or \write filename, \w or \write |command
Outputs the current query buffer to the file filename or pipes it to the shell command
command.
\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 a
pattern is specified, only tables, views and sequences whose names match the pattern
are listed.
This is an alias for \dp (“display privileges”).
\! [ command ]
Escapes to a separate shell or executes the shell command command. 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 a pattern parameter to specify the object name(s) to be
displayed. In the simplest case, a pattern is just the exact name of the object. The
characters within a pattern are normally folded to lower case, just as in SQL names;
for example, \dt FOO will display the table named foo. As in SQL names, placing double
quotes around a pattern stops folding to lower case. Should you need to include an
actual double quote character in a pattern, write it as a pair of double quotes within
a double-quote sequence; again this is in accord with the rules for SQL quoted
identifiers. For example, \dt "FOO""BAR" will display the table named FOO"BAR (not
foo"bar). Unlike the normal rules for SQL names, you can put double quotes around just
part of a pattern, for instance \dt FOO"FOO"BAR will display the table named
fooFOObar.
Whenever the pattern parameter is omitted completely, the \d commands display all
objects that are visible in the current schema search path — this is equivalent to
using * as the pattern. (An object is said to be visible if its containing schema is
in the search path and no object of the same kind and name appears earlier in the
search path. This is equivalent to the statement that the object can be referenced by
name without explicit schema qualification.) To see all objects in the database
regardless of visibility, use *.* as the pattern.
Within a pattern, * matches any sequence of characters (including no characters) and ?
matches any single character. (This notation is comparable to Unix shell file name
patterns.) For example, \dt int* displays tables whose names begin with int. But
within double quotes, * and ? lose these special meanings and are just matched
literally.
A pattern that contains a dot (.) is interpreted as a schema name pattern followed by
an object name pattern. For example, \dt foo*.*bar* displays all tables whose table
name includes bar that are in schemas whose schema name starts with foo. When no dot
appears, then the pattern matches only objects that are visible in the current schema
search path. Again, a dot within double quotes loses its special meaning and is
matched literally.
Advanced users can use regular-expression notations such as character classes, for
example [0-9] to match any digit. All regular expression special characters work as
specified in Section 9.7.3, “POSIX Regular Expressions”, in the documentation, except
for . which is taken as a separator as mentioned above, * which is translated to the
regular-expression notation .*, ? which is translated to ., and $ which is matched
literally. You can emulate these pattern characters at need by writing ? for ., (R+|)
for R*, or (R|) for R?. $ is not needed as a regular-expression character since the
pattern must match the whole name, unlike the usual interpretation of regular
expressions (in other words, $ is automatically appended to your pattern). Write * at
the beginning and/or end if you don't wish the pattern to be anchored. Note that
within double quotes, all regular expression special characters lose their special
meanings and are matched literally. Also, the regular expression special characters
are matched literally in operator name patterns (i.e., the argument of \do).
Advanced Features
Variables
psql provides variable substitution features similar to common Unix command shells.
Variables are simply name/value pairs, where the value can be any string of any
length. The name must consist of letters (including non-Latin letters), digits, and
underscores.
To set a variable, use the psql meta-command \set. For example,
testdb=> \set foo bar
sets the variable foo to the value bar. To retrieve the content of the variable,
precede the name with a colon, for example:
testdb=> \echo :foo
bar
This works in both regular SQL commands and meta-commands; there is more detail in SQL
Interpolation, below.
If you call \set without a second argument, the variable is set, with an empty string
as value. To unset (i.e., delete) a variable, use the command \unset. To show the
values of all variables, call \set without any argument.
Note
The arguments of \set are subject to the same substitution rules as with other
commands. Thus you can construct interesting references such as \set :foo
'something' and get “soft links” or “variable variables” of Perl or PHP fame,
respectively. Unfortunately (or fortunately?), there is no way to do anything
useful with these constructs. On the other hand, \set bar :foo is a perfectly
valid way to copy a variable.
A number of these variables are treated specially by psql. They represent certain
option settings that can be changed at run time by altering the value of the variable,
or in some cases represent changeable state of psql. Although you can use these
variables for other purposes, this is not recommended, as the program behavior might
grow really strange really quickly. By convention, all specially treated variables'
names consist of all upper-case ASCII letters (and possibly digits and underscores).
To ensure maximum compatibility in the future, avoid using such variable names for
your own purposes. A list of all specially treated variables follows.
AUTOCOMMIT
When on (the default), each SQL command is automatically committed upon successful
completion. To postpone commit in this mode, you must enter a BEGIN or START
TRANSACTION SQL command. When off or unset, SQL commands are not committed until
you explicitly issue COMMIT or END. The autocommit-off mode works by issuing an
implicit BEGIN for you, just before any command that is not already in a
transaction block and is not itself a BEGIN or other transaction-control command,
nor a command that cannot be executed inside a transaction block (such as VACUUM).
Note
In autocommit-off mode, you must explicitly abandon any failed transaction by
entering ABORT or ROLLBACK. Also keep in mind that if you exit the session
without committing, your work will be lost.
Note
The autocommit-on mode is 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.
COMP_KEYWORD_CASE
Determines which letter case to use when completing an SQL key word. If set to
lower or upper, the completed word will be in lower or upper case, respectively.
If set to preserve-lower or preserve-upper (the default), the completed word will
be in the case of the word already entered, but words being completed without
anything entered will be in lower or upper case, respectively.
DBNAME
The name of the database you are currently connected to. This is set every time
you connect to a database (including program start-up), but can be unset.
ECHO
If set to all, all nonempty input lines are printed to standard output as they are
read. (This does not apply to lines read interactively.) To select this behavior
on program start-up, use the switch -a. If set to queries, psql prints each query
to standard output as it is sent to the server. The switch for this is -e.
ECHO_HIDDEN
When this variable is set to on and a backslash command queries the database, the
query is first shown. This feature helps you to study 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_import
command. This variable is only guaranteed to be valid until after the result of
the next SQL command has been displayed.
ON_ERROR_ROLLBACK
When set to on, if a statement in a transaction block generates an error, the
error is ignored and the transaction continues. When set to interactive, such
errors are only ignored in interactive sessions, and not when reading script
files. When unset or set to off, a statement in a transaction block that generates
an error aborts the entire transaction. The error rollback mode works by issuing
an implicit SAVEPOINT for you, just before each command that is in a transaction
block, and then rolling back to the savepoint if the command fails.
ON_ERROR_STOP
By default, command processing continues after an error. When this variable is set
to on, processing will instead stop immediately. In interactive mode, psql will
return to the command prompt; otherwise, psql will exit, returning error code 3 to
distinguish this case from fatal error conditions, which are reported using error
code 1. In either case, any currently running scripts (the top-level script, if
any, and any other scripts which it may have in invoked) will be terminated
immediately. If the top-level command string contained multiple SQL commands,
processing will stop with the current command.
PORT
The database server port to which you are currently connected. This is set every
time you connect to a database (including program start-up), but can be unset.
PROMPT1, PROMPT2, PROMPT3
These specify what the prompts psql issues should look like. See Prompting below.
QUIET
Setting this variable to on is equivalent to the command line option -q. It is
probably not too useful in interactive mode.
SINGLELINE
Setting this variable to on is equivalent to the command line option -S.
SINGLESTEP
Setting this variable to on is equivalent to the command line option -s.
USER
The database user you are currently connected as. This is set every time you
connect to a database (including program start-up), but can be unset.
VERBOSITY
This variable can be set to the values default, verbose, or terse to control the
verbosity of error reports.
SQL Interpolation
A key feature of psql variables is that you can substitute (“interpolate”) them into
regular SQL statements, as well as the arguments of meta-commands. Furthermore, psql
provides facilities for ensuring that variable values used as SQL literals and
identifiers are properly quoted. The syntax for interpolating a value without any
quoting is to prepend the variable name with a colon (:). For example,
testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;
would query the table my_table. Note that this may be unsafe: the value of the
variable is copied literally, so it can contain unbalanced quotes, or even backslash
commands. You must make sure that it makes sense where you put it.
When a value is to be used as an SQL literal or identifier, it is safest to arrange
for it to be quoted. To quote the value of a variable as an SQL literal, write a colon
followed by the variable name in single quotes. To quote the value as an SQL
identifier, write a colon followed by the variable name in double quotes. These
constructs deal correctly with quotes and other special characters embedded within the
variable value. The previous example would be more safely written this way:
testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :"foo";
Variable interpolation will not be performed within quoted SQL literals and
identifiers. Therefore, a construction such as ':foo' doesn't work to produce a quoted
literal from a variable's value (and it would be unsafe if it did work, since it
wouldn't correctly handle quotes embedded in the value).
One example use of this mechanism is to copy the contents of a file into a table
column. First load the file into a variable and then interpolate the variable's value
as a quoted string:
testdb=> \set content `cat my_file.txt`
testdb=> INSERT INTO my_table VALUES (:'content');
(Note that this still won't work if my_file.txt contains NUL bytes. psql does not
support embedded NUL bytes in variable values.)
Since colons can legally appear in SQL commands, an apparent attempt at interpolation
(that is, :name, :'name', or :"name") is not replaced unless the named variable is
currently set. In any case, you can escape a colon with a backslash to protect it from
substitution.
The colon syntax for variables is standard SQL for embedded query languages, such as
ECPG. The colon syntaxes for array slices and type casts are PostgreSQL extensions,
which can sometimes conflict with the standard usage. The colon-quote syntax for
escaping a variable's value as an SQL literal or identifier is a psql extension.
Prompting
The prompts psql issues can be customized to your preference. The three variables
PROMPT1, PROMPT2, and PROMPT3 contain strings and special escape sequences that
describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued
when psql requests a new command. Prompt 2 is issued when more input is expected
during command entry, for example because the command was not terminated with a
semicolon or a quote was not closed. Prompt 3 is issued when you are running an SQL
COPY FROM STDIN command and you need to type in a row value 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, or ! if the session is
disconnected from the database (which can happen if \connect fails). In prompt 2
%R is replaced by a character that depends on why psql expects more input: - if
the command simply wasn't terminated yet, but * if there is an unfinished /* ...
*/ comment, a single quote if there is an unfinished quoted string, a double quote
if there is an unfinished quoted identifier, a dollar sign if there is an
unfinished dollar-quoted string, or ( if there is an unmatched left parenthesis.
In prompt 3 %R doesn't produce anything.
%x
Transaction status: an empty string when not in a transaction block, or * when in
a transaction block, or ! when in a failed transaction block, or ? when the
transaction state is indeterminate (for example, because there is no connection).
%digits
The character with the indicated octal code is substituted.
%:name:
The value of the psql variable name. See the section Variables for details.
%`command`
The output of command, similar to ordinary “back-tick” substitution.
%[ ... %]
Prompts can contain terminal control characters which, for example, change the
color, background, or style of the prompt text, or change the title of the
terminal window. In order for the line editing features of Readline to work
properly, these non-printing control characters must be designated as invisible by
surrounding them with %[ and %]. Multiple pairs of these can occur within the
prompt. For example:
testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '
results in a boldfaced (1;) yellow-on-black (33;40) prompt on VT100-compatible,
color-capable terminals.
To insert a percent sign into your prompt, write %%. The default prompts are '%/%R%# '
for prompts 1 and 2, and '>> ' for prompt 3.
Note
This feature was shamelessly plagiarized from tcsh.
Command-Line Editing
psql supports the Readline library for convenient line editing and retrieval. The
command history is automatically saved when psql exits and is reloaded when psql
starts up. Tab-completion is also supported, although the completion logic makes no
claim to be an SQL parser. 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 psql
set disable-completion on
$endif
(This is not a psql but a Readline feature. Read its documentation for further
details.)
ENVIRONMENT
COLUMNS
If \pset columns is zero, controls the width for the wrapped format and width for
determining if wide output requires the pager or should be switched to the vertical
format in expanded auto mode.
PAGER
If the query results do not fit on the screen, they are piped through this command.
Typical values are more or less. The default is platform-dependent. Use of the pager
can be disabled by setting PAGER to empty, or by using pager-related options of the
\pset command.
PGDATABASE, PGHOST, PGPORT, PGUSER
Default connection parameters (see Section 31.14, “Environment Variables”, in the
documentation).
PSQL_EDITOR, EDITOR, VISUAL
Editor used by the \e and \ef commands. The variables are examined in the order
listed; the first that is set is used.
The built-in default editors are vi on Unix systems and notepad.exe on Windows
systems.
PSQL_EDITOR_LINENUMBER_ARG
When \e or \ef is used with a line number argument, this variable specifies the
command-line argument used to pass the starting line number to the user's editor. For
editors such as Emacs or vi, this is a plus sign. Include a trailing space in the
value of the variable if there needs to be space between the option name and the line
number. Examples:
PSQL_EDITOR_LINENUMBER_ARG='+'
PSQL_EDITOR_LINENUMBER_ARG='--line '
The default is + on Unix systems (corresponding to the default editor vi, and useful
for many other common editors); but there is no default on Windows systems.
PSQL_HISTORY
Alternative location for the command history file. Tilde (~) expansion is performed.
PSQLRC
Alternative location of the user's .psqlrc file. Tilde (~) expansion is performed.
SHELL
Command executed by the \! command.
TMPDIR
Directory for storing temporary files. The default is /tmp.
This utility, like most other PostgreSQL utilities, also uses the environment variables
supported by libpq (see Section 31.14, “Environment Variables”, in the documentation).
FILES
psqlrc and ~/.psqlrc
Unless it is passed an -X or -c option, psql attempts to read and execute commands
from the system-wide startup file (psqlrc) and then the user's personal startup file
(~/.psqlrc), after connecting to the database but before accepting normal commands.
These files can be used to set up the client and/or the server to taste, typically
with \set and SET commands.
The system-wide startup file is named psqlrc and is sought in the installation's
“system configuration” directory, which is most reliably identified by running
pg_config --sysconfdir. By default this directory will be ../etc/ relative to the
directory containing the PostgreSQL executables. The name of this directory can be set
explicitly via the PGSYSCONFDIR environment variable.
The user's personal startup file is named .psqlrc and is sought in the invoking user's
home directory. On Windows, which lacks such a concept, the personal startup file is
named %APPDATA%\postgresql\psqlrc.conf. The location of the user's startup file can be
set explicitly via the PSQLRC environment variable.
Both the system-wide startup file and the user's personal startup file can be made
psql-version-specific by appending a dash and the PostgreSQL major or minor release
number to the file name, for example ~/.psqlrc-9.2 or ~/.psqlrc-9.2.5. The most
specific version-matching file will be read in preference to a non-version-specific
file.
.psql_history
The command-line history is stored in the file ~/.psql_history, or
%APPDATA%\postgresql\psql_history on Windows.
The location of the history file can be set explicitly via the PSQL_HISTORY
environment variable.
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 works best with servers of the same or an older major version. 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. The general
functionality of running SQL commands and displaying query results should also work
with servers of a newer major version, but this cannot be guaranteed in all cases.
If you want to use psql to connect to several servers of different major versions, it
is recommended that you use the newest version of psql. Alternatively, you can keep a
copy of psql from each major version around and be sure to use the version that
matches the respective server. But in practice, this additional complication should
not be necessary.
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