psql(1)
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.)
-b
--echo-errors
Print failed SQL commands to standard error output. This is
equivalent to setting the variable ECHO to errors.
-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[=topic]
Show help about psql and exit. The optional topic parameter
(defaulting to options) selects which part of psql is explained:
commands describes psql's backslash commands; options describes the
command-line options that can be passed to psql; and variables
shows help about psql configuration variables.
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 (9.5.5)
Type "help" for help.
testdb=>
At the prompt, the user can type in SQL commands. Ordinarily, input
lines are sent to the server when a command-terminating semicolon is
reached. An end of line does not terminate a command. Thus commands can
be spread over several lines for clarity. If the command was sent and
executed without error, the results of the command are displayed on the
screen.
Whenever a command is executed, psql also polls for asynchronous
notification events generated by LISTEN(7) and NOTIFY(7).
While C-style block comments are passed to the server for processing
and removal, SQL-standard comments are removed by psql.
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), (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:
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
passed from or to command is routed between the server and the
client. Again, the execution privileges are those of the local
user, not the server, and no SQL superuser privileges are required.
For \copy ... from stdin, data rows are read from the same source
that issued the command, continuing until \. is read or the stream
reaches EOF. This option is useful for populating tables in-line
within a SQL script file. For \copy ... to stdout, output is sent
to the same place as psql command output, and the COPY count
command status is not printed (since it might be confused with a
data row). To read/write psql's standard input or output regardless
of the current command source or \o option, write from pstdin or to
pstdout.
The syntax of this command is similar to that of the SQL COPY(7)
command. All options other than the data source/destination are as
specified for COPY(7). Because of this, special parsing rules apply
to the \copy command. In particular, psql's variable substitution
rules and backslash escapes do not apply.
Tip
This operation is not as efficient as 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, sequence, or foreign table)
or composite type matching the pattern, show all columns, their
types, the tablespace (if not the default) and any special
attributes such as NOT NULL or defaults. Associated indexes,
constraints, rules, and triggers are also shown. For foreign
tables, the associated foreign server is shown as well. ("Matching
the pattern" is defined in Patterns below.)
For some types of relation, \d shows additional information for
each column: column values for sequences, indexed expression for
indexes and foreign data wrapper options for foreign tables.
The command form \d+ is identical, except that more information is
displayed: any comments associated with the columns of the table
are shown, as is the presence of OIDs in the table, the view
definition if the relation is a view, a non-default replica
identity setting.
By default, only user-created objects are shown; supply a pattern
or the S modifier to include system objects.
Note
If \d is used without a pattern argument, it is equivalent to
\dtvsE which will show a list of all visible tables, views,
sequences and foreign tables. This is purely a convenience
measure.
\da[S] [ pattern ]
Lists aggregate functions, together with their return type and the
data types they operate on. If pattern is specified, only
aggregates whose names match the pattern are shown. By default,
only user-created objects are shown; supply a pattern or the S
modifier to include system objects.
\db[+] [ pattern ]
Lists tablespaces. If pattern is specified, only tablespaces whose
names match the pattern are shown. If + is appended to the command
name, each tablespace is listed with its associated options,
on-disk size, permissions and description.
\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. By default, only user-created objects
are shown; supply a pattern or the S modifier to include system
objects. If the form \df+ is used, additional information about
each function is shown, including security classification,
volatility, owner, language, source code and description.
Tip
To look up functions taking arguments or returning values of a
specific type, use your pager's search capability to scroll
through the \df output.
\dF[+] [ pattern ]
Lists text search configurations. 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 result 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. If + is appended to
the command name, additional information about each operator is
shown, currently just the name of the underlying function.
\dO[S+] [ pattern ]
Lists collations. 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.
\pset without any arguments displays the current status of all
printing options.
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 details
depend on the particular format. In HTML format, this will
translate directly into the border=... attribute. In most
other formats only values 0 (no border), 1 (internal dividing
lines), and 2 (table frame) make sense, and values above 2 will
be treated the same as border = 2. The latex and
latex-longtable formats additionally allow a value of 3 to add
dividing lines between data rows.
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, asciidoc, 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, asciidoc, 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, the linestyle
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.
pager_min_lines
If pager_min_lines is set to a number greater than the page
height, the pager program will not be called unless there are
at least this many lines of output to show. The default setting
is 0.
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.
unicode_border_linestyle
Sets the border drawing style for the unicode line style to one
of single or double.
unicode_column_linestyle
Sets the column drawing style for the unicode line style to one
of single or double.
unicode_header_linestyle
Sets the header drawing style for the unicode line style to one
of single or double.
Illustrations of how these different formats look can be seen in
the EXAMPLES section.
Tip
There are various shortcut commands for \pset. See
, \C, \H,
\t, \T, and \x.
\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.
\? [ topic ]
Shows help information. The optional topic parameter (defaulting to
commands) selects which part of psql is explained: commands
describes psql's backslash commands; options describes the
command-line options that can be passed to psql; and variables
shows help about psql configuration variables.
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. If set to errors, then only failed queries are
displayed on standard error output. The switch for this is -b.
If unset, or if set to none (or any other value than those
above) then no queries are displayed.
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 none (or 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).
%l
The line number inside the current statement, starting from 1.
%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. The use of the pager can be disabled by
using 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=>
\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
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