psql(1)
PSQL(1) PostgreSQL Client Applications 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 Post-
greSQL, 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 writ-
ing scripts and automating a wide variety of tasks.
OPTIONS
-a
--echo-all
Print all input lines to standard output as they are
read. This is more useful for script processing rather
than interactive mode. This is equivalent to setting
the variable ECHO to all.
-A
--no-align
Switches to unaligned output mode. (The default output
mode is otherwise aligned.)
-c command
--command command
Specifies that psql is to execute one command string,
command, and then exit. This is useful in shell
scripts.
command must be either a command string that is com-
pletely parsable by the server (i.e., it contains no
psql specific features), or a single backslash command.
Thus you cannot mix SQL and psql meta-commands with
this option. To achieve that, you could pipe the string
into psql, like this: echo '\x \\ SELECT * FROM foo;' |
psql. (\\ is the separator meta-command.)
If the command string contains multiple SQL commands,
they are processed in a single transaction, unless
there are explicit BEGIN/COMMIT commands included in
the string to divide it into multiple transactions.
This is different from the behavior when the same
string is fed to psql's standard input.
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-d dbname
--dbname dbname
Specifies the name of the database to connect to. This
is equivalent to specifying dbname as the first non-
option argument on the command line.
-e
--echo-queries
Copy all SQL commands sent to the server to standard
output as well. This is equivalent to setting the
variable ECHO to queries.
-E
--echo-hidden
Echo the actual queries generated by \d and other
backslash commands. You can use this to study psql's
internal operations. This is equivalent to setting the
variable ECHO_HIDDEN from within psql.
-f filename
--file filename
Use the file filename as the source of commands instead
of reading commands interactively. After the file is
processed, psql terminates. This is in many ways
equivalent to the internal command \i.
If filename is - (hyphen), then standard input is read.
Using this option is subtly different from writing psql
< filename. In general, both will do what you expect,
but using -f enables some nice features such as error
messages with line numbers. There is also a slight
chance that using this option will reduce the start-up
overhead. On the other hand, the variant using the
shell's input redirection is (in theory) guaranteed to
yield exactly the same output that you would have got-
ten had you entered everything by hand.
-F separator
--field-separator separator
Use separator as the field separator for unaligned out-
put. This is equivalent to \pset fieldsep or \f.
-h hostname
--host hostname
Specifies the host name of the machine on which the
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server is running. If the value begins with a slash, it
is used as the directory for the Unix-domain socket.
-H
--html
Turn on HTML tabular output. This is equivalent to
\pset format html or the \H command.
-l
--list
List all available databases, then exit. Other non-
connection options are ignored. This is similar to the
internal command \list.
-L filename
--log-file filename
Write all query output into file filename, in addition
to the normal output destination.
-o filename
--output filename
Put all query output into file filename. This is
equivalent to the command \o.
-p port
--port port
Specifies the TCP port or the local Unix-domain socket
file extension on which the server is listening for
connections. Defaults to the value of the PGPORT
environment variable or, if not set, to the port speci-
fied at compile time, usually 5432.
-P assignment
--pset assignment
Allows you to specify printing options in the style of
\pset on the command line. Note that here you have to
separate name and value with an equal sign instead of a
space. Thus to set the output format to LaTeX, you
could write -P format=latex.
-q
--quiet
Specifies that psql should do its work quietly. By
default, it prints welcome messages and various infor-
mational output. If this option is used, none of this
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happens. This is useful with the -c option. Within
psql you can also set the QUIET variable to achieve the
same effect.
-R separator
--record-separator separator
Use separator as the record separator for unaligned
output. This is equivalent to the \pset recordsep com-
mand.
-s
--single-step
Run in single-step mode. That means the user is
prompted before each command is sent to the server,
with the option to cancel execution as well. Use this
to debug scripts.
-S
--single-line
Runs in single-line mode where a newline terminates an
SQL command, as a semicolon does.
Note: This mode is provided for those who insist on it,
but you are not necessarily encouraged to use it. In
particular, if you mix SQL and meta-commands on a line
the order of execution might not always be clear to the
inexperienced user.
-t
--tuples-only
Turn off printing of column names and result row count
footers, etc. This is equivalent to the \t command.
-T table_options
--table-attr table_options
Allows you to specify options to be placed within the
HTML table tag. See \pset for details.
-u Forces psql to prompt for the user name and password
before connecting to the database.
This option is deprecated, as it is conceptually
flawed. (Prompting for a non-default user name and
prompting for a password because the server requires it
are really two different things.) You are encouraged to
look at the -U and -W options instead.
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-U username
--username username
Connect to the database as the user username instead of
the default. (You must have permission to do so, of
course.)
-v assignment
--set assignment
--variable assignment
Perform a variable assignment, like the \set internal
command. Note that you must separate name and value, if
any, by an equal sign on the command line. To unset a
variable, leave off the equal sign. To just set a vari-
able without a value, use the equal sign but leave off
the value. These assignments are done during a very
early stage of start-up, so variables reserved for
internal purposes might get overwritten later.
-V
--version
Print the psql version and exit.
-W
--password
Forces psql to prompt for a password before connecting
to a database.
psql should automatically prompt for a password when-
ever the server requests password authentication. How-
ever, currently password request detection is not
totally reliable, hence this option to force a prompt.
If no password prompt is issued and the server requires
password authentication, the connection attempt will
fail.
This option will remain set for the entire session,
even if you change the database connection with the
meta-command \connect.
-x
--expanded
Turn on the expanded table formatting mode. This is
equivalent to the \x command.
-X,
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--no-psqlrc
Do not read the start-up file (neither the system-wide
psqlrc file nor the user's ~/.psqlrc file).
-1
--single-transaction
When psql executes a script with the -f option, adding
this option wraps BEGIN/COMMIT around the script to
execute it as a single transaction. This ensures that
either all the commands complete successfully, or no
changes are applied.
If the script itself uses BEGIN, COMMIT, or ROLLBACK,
this option will not have the desired effects. Also,
if the script contains any command that cannot be exe-
cuted inside a transaction block, specifying this
option will cause that command (and hence the whole
transaction) to fail.
-?
--help
Show help about psql command line arguments, and exit.
EXIT STATUS
psql returns 0 to the shell if it finished normally, 1 if a
fatal error of its own (out of memory, file not found)
occurs, 2 if the connection to the server went bad and the
session was not interactive, and 3 if an error occurred in a
script and the variable ON_ERROR_STOP was set.
USAGE
CONNECTING TO A DATABASE
psql is a regular PostgreSQL client application. In order to
connect to a database you need to know the name of your tar-
get database, the host name and port number of the server
and what user name you want to connect as. psql can be told
about those parameters via command line options, namely -d,
-h, -p, and -U respectively. If an argument is found that
does not belong to any option it will be interpreted as the
database name (or the user name, if the database name is
already given). Not all these options are required; there
are useful defaults. If you omit the host name, psql will
connect via a Unix-domain socket to a server on the local
host, or via TCP/IP to localhost on machines that don't have
Unix-domain sockets. The default port number is determined
at compile time. Since the database server uses the same
default, you will not have to specify the port in most
cases. The default user name is your Unix user name, as is
the default database name. Note that you can't just connect
to any database under any user name. Your database
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administrator should have informed you about your access
rights.
When the defaults aren't quite right, you can save yourself
some typing by setting the environment variables PGDATABASE,
PGHOST, PGPORT and/or PGUSER to appropriate values. (For
additional environment variables, see in the documentation.)
It is also convenient to have a ~/.pgpass file to avoid reg-
ularly having to type in passwords. See in the documentation
for more information.
If the connection could not be made for any reason (e.g.,
insufficient privileges, server is not running on the tar-
geted host, etc.), psql will return an error and terminate.
ENTERING SQL COMMANDS
In normal operation, psql provides a prompt with the name of
the database to which psql is currently connected, followed
by the string =>. For example,
$ psql testdb
Welcome to psql 8.2.6, the PostgreSQL interactive terminal.
Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit
testdb=>
At the prompt, the user may type in SQL commands. Ordi-
narily, 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 exe-
cuted without error, the results of the command are
displayed on the screen.
Whenever a command is executed, psql also polls for asyn-
chronous notification events generated by LISTEN [listen(5)]
and NOTIFY [notify(5)].
META-COMMANDS
Anything you enter in psql that begins with an unquoted
backslash is a psql meta-command that is processed by psql
itself. These commands help make psql more useful for
administration or scripting. Meta-commands are more commonly
called slash or backslash commands.
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The format of a psql command is the backslash, followed
immediately by a command verb, then any arguments. The argu-
ments are separated from the command verb and each other by
any number of whitespace characters.
To include whitespace into an argument you may quote it with
a single quote. To include a single quote into such an argu-
ment, use two single quotes. Anything contained in single
quotes is furthermore subject to C-like substitutions for \n
(new line), \t (tab), \digits (octal), and \xdigits (hexade-
cimal).
If an unquoted argument begins with a colon (:), it is taken
as a psql variable and the value of the variable is used as
the argument instead.
Arguments that are enclosed in backquotes (`) are taken as a
command line that is passed to the shell. The output of the
command (with any trailing newline removed) is taken as the
argument value. The above escape sequences also apply in
backquotes.
Some commands take an SQL identifier (such as a table name)
as argument. These arguments follow the syntax rules of SQL:
Unquoted letters are forced to lowercase, while double
quotes (") protect letters from case conversion and allow
incorporation of whitespace into the identifier. Within dou-
ble quotes, paired double quotes reduce to a single double
quote in the resulting name. For example, FOO"BAR"BAZ is
interpreted as fooBARbaz, and "A weird"" name" becomes A
weird" name.
Parsing for arguments stops when another unquoted backslash
occurs. This is taken as the beginning of a new meta-
command. The special sequence \\ (two backslashes) marks the
end of arguments and continues parsing SQL commands, if any.
That way SQL and psql commands can be freely mixed on a
line. But in any case, the arguments of a meta-command can-
not 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 compa-
tibility. See \pset for a more general solution.
Changes the current working directory to directory.
Without argument, changes to the current user's home
directory.
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Tip: To print your current working directory, use
\!pwd.
C [ title ]
Sets the title of any tables being printed as the
result of a query or unset any such title. This command
is equivalent to \pset title title. (The name of this
command derives from ``caption'', as it was previously
only used to set the caption in an HTML table.)
Establishes a new connection to a PostgreSQL server. If
the new connection is successfully made, the previous
connection is closed. If any of dbname, username, host
or port are omitted or specified as -, the value of
that parameter from the previous connection is used. If
there is no previous connection, the libpq default for
the parameter's value is used.
If the connection attempt failed (wrong user name,
access denied, etc.), the previous connection will only
be kept if psql is in interactive mode. When executing
a non-interactive script, processing will immediately
stop with an error. This distinction was chosen as a
user convenience against typos on the one hand, and a
safety mechanism that scripts are not accidentally act-
ing on the wrong database on the other hand.
Performs a frontend (client) copy. This is an operation
that runs an SQL COPY [copy(5)] command, but instead of
the server reading or writing the specified file, psql
reads or writes the file and routes the data between
the server and the local file system. This means that
file accessibility and privileges are those of the
local user, not the server, and no SQL superuser
privileges are required.
The syntax of the command is similar to that of the SQL
COPY [copy(5)] command. Note that, because of this,
special parsing rules apply to the \copy command. In
particular, the variable substitution rules and
backslash escapes do not apply.
\copy ... from stdin | to stdout reads/writes based on
the command input and output respectively. All rows
are read from the same source that issued the command,
continuing until \. is read or the stream reaches EOF.
Output is sent to the same place as command output. To
read/write from psql's standard input or output, use
pstdin or pstdout. This option is useful for populating
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tables in-line within a SQL script file.
Tip: This operation is not as efficient as the SQL COPY
command because all data must pass through the
client/server connection. For large amounts of data the
SQL command may be preferable.
Shows the copyright and distribution terms of Post-
greSQL.
[ pattern ]
+ [ pattern ]
For each relation (table, view, index, or sequence)
matching the pattern, show all columns, their types,
the tablespace (if not the default) and any special
attributes such as NOT NULL or defaults, if any. Asso-
ciated indexes, constraints, rules, and triggers are
also shown, as is the view definition if the relation
is a view. (``Matching the pattern'' is defined
below.)
The command form \d+ is identical, except that more
information is displayed: any comments associated with
the columns of the table are shown, as is the presence
of OIDs in the table.
Note: If \d is used without a pattern argument, it is
equivalent to \dtvs which will show a list of all
tables, views, and sequences. This is purely a conveni-
ence measure.
a [ pattern ]
Lists all available aggregate functions, together with
the data types they operate on. If pattern is speci-
fied, only aggregates whose names match the pattern are
shown.
b [ pattern ]
b+ [ pattern ]
Lists all available tablespaces. If pattern is speci-
fied, only tablespaces whose names match the pattern
are shown. If + is appended to the command name, each
object is listed with its associated permissions.
c [ pattern ]
Lists all available conversions between character-set
encodings. If pattern is specified, only conversions
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whose names match the pattern are listed.
C Lists all available type casts.
d [ pattern ]
Shows the descriptions of objects matching the pattern,
or of all visible objects if no argument is given. But
in either case, only objects that have a description
are listed. (``Object'' covers aggregates, functions,
operators, types, relations (tables, views, indexes,
sequences, large objects), rules, and triggers.) For
example:
=> \dd version
Object descriptions
Schema | Name | Object | Description
------------+---------+----------+---------------------------
pg_catalog | version | function | PostgreSQL version string
(1 row)
Descriptions for objects can be created with the COM-
MENT [comment(5)] SQL command.
D [ pattern ]
Lists all available domains. If pattern is specified,
only matching domains are shown.
f [ pattern ]
f+ [ pattern ]
Lists available functions, together with their argument
and return types. If pattern is specified, only func-
tions whose names match the pattern are shown. If the
form \df+ is used, additional information about each
function, including language and description, is shown.
Note:
To look up functions taking argument or returning
values of a specific type, use your pager's search
capability to scroll through the \df output.
To reduce clutter, \df does not show data type I/O
functions. This is implemented by ignoring functions
that accept or return type cstring.
g [ pattern ]
Lists all database roles. If pattern is specified, only
those roles whose names match the pattern are listed.
(This command is now effectively the same as \du.)
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istvS [ pattern ]
This is not the actual command name: the letters i, s,
t, v, S stand for index, sequence, table, view, and
system table, respectively. You can specify any or all
of these letters, in any order, to obtain a listing of
all the matching objects. The letter S restricts the
listing to system objects; without S, only non-system
objects are shown. If + is appended to the command
name, each object is listed with its associated
description, if any.
If pattern is specified, only objects whose names match
the pattern are listed.
l This is an alias for \lo_list, which shows a list of
large objects.
n [ pattern ]
n+ [ pattern ]
Lists all available schemas (namespaces). If pattern (a
regular expression) is specified, only schemas whose
names match the pattern are listed. Non-local tem-
porary schemas are suppressed. If + is appended to the
command name, each object is listed with its associated
permissions and description, if any.
o [ pattern ]
Lists available operators with their operand and return
types. If pattern is specified, only operators whose
names match the pattern are listed.
p [ pattern ]
Produces a list of all available tables, views and
sequences with their associated access privileges. If
pattern is specified, only tables, views and sequences
whose names match the pattern are listed.
The GRANT [grant(5)] and REVOKE [revoke(5)] commands
are used to set access privileges.
T [ pattern ]
T+ [ pattern ]
Lists all data types or only those that match pattern.
The command form \dT+ shows extra information.
u [ pattern ]
Lists all database roles, or only those that match pat-
tern.
\dit (or \) [ filename ]
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If filename is specified, the file is edited; after the
editor exits, its content is copied back to the query
buffer. If no argument is given, the current query
buffer is copied to a temporary file which is then
edited in the same fashion.
The new query buffer is then re-parsed according to the
normal rules of psql, where the whole buffer is treated
as a single line. (Thus you cannot make scripts this
way. Use \i for that.) This means also that if the
query ends with (or rather contains) a semicolon, it is
immediately executed. In other cases it will merely
wait in the query buffer.
Tip: psql searches the environment variables
PSQL_EDITOR, EDITOR, and VISUAL (in that order) for an
editor to use. If all of them are unset, vi is used on
Unix systems, notepad.exe on Windows systems.
\cho text [ ... ]
Prints the arguments to the standard output, separated
by one space and followed by a newline. This can be
useful to intersperse information in the output of
scripts. For example:
=> \echo `date`
Tue Oct 26 21:40:57 CEST 1999
If the first argument is an unquoted -n the trailing
newline is not written.
Tip: If you use the \o command to redirect your query
output you may wish to use \qecho instead of this com-
mand.
\ncoding [ encoding ]
Sets the client character set encoding. Without an
argument, this command shows the current encoding.
[ 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.
[ { filename | |command } ]
Sends the current query input buffer to the server and
optionally stores the query's output in filename or
pipes the output into a separate Unix shell executing
command. A bare \g is virtually equivalent to a semi-
colon. A \g with argument is a ``one-shot'' alternative
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to the \o command.
p (or [ command ]
Gives syntax help on the specified SQL command. If com-
mand is not specified, then psql will list all the com-
mands 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.
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 con-
venience, but see \pset about setting other output
options.
i filename
Reads input from the file filename and executes it as
though it had been typed on the keyboard.
Note: If you want to see the lines on the screen as
they are read you must set the variable ECHO to all.
List the names, owners, and character set encodings of all
the databases in the server. If + is appended to the
command name, database descriptions are also displayed.
rt 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.
rt filename [ comment ]
Stores the file into a PostgreSQL large object. Option-
ally, it associates the given comment with the object.
Example:
foo=> \lo_import '/home/peter/pictures/photo.xcf' 'a picture of me'
lo_import 152801
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The response indicates that the large object received
object ID 152801 which one ought to remember if one
wants to access the object ever again. For that reason
it is recommended to always associate a human-readable
comment with every object. Those can then be seen with
the \lo_list command.
Note that this command is subtly different from the
server-side lo_import because it acts as the local user
on the local file system, rather than the server's user
and file system.
Shows a list of all PostgreSQL large objects currently
stored in the database, along with any comments pro-
vided for them.
id Deletes the large object with OID loid from the data-
base.
Tip: Use \lo_list to find out the large object's OID.
[ {filename | |command} ]
Saves future query results to the file filename or
pipes future results into a separate Unix shell to exe-
cute command. If no arguments are specified, the query
output will be reset to the standard output.
``Query results'' includes all tables, command
responses, and notices obtained from the database
server, as well as output of various backslash commands
that query the database (such as \d), but not error
messages.
Tip: To intersperse text output in between query
results, use \qecho.
Print
the current query buffer to the standard output.
assword [ 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 pass-
word does not appear in cleartext in the command his-
tory, the server log, or elsewhere.
set parameter [ value ]
This command sets options affecting the output of query
result tables. parameter describes which option is to
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be set. The semantics of value depend thereon.
Adjustable printing options are:
format
Sets the output format to one of unaligned,
aligned, html, latex, or troff-ms. Unique abbre-
viations are allowed. (That would mean one letter
is enough.)
``Unaligned'' writes all columns of a row on a
line, separated by the currently active field
separator. This is intended to create output that
might be intended to be read in by other programs
(tab-separated, comma-separated). ``Aligned''
mode is the standard, human-readable, nicely for-
matted text output that is default. The ``HTML''
and ``LaTeX'' modes put out tables that are
intended to be included in documents using the
respective mark-up language. They are not complete
documents! (This might not be so dramatic in HTML,
but in LaTeX you must have a complete document
wrapper.)
border
The second argument must be a number. In general,
the higher the number the more borders and lines
the tables will have, but this depends on the par-
ticular format. In HTML mode, this will translate
directly into the border=... attribute, in the
others only values 0 (no border), 1 (internal
dividing lines), and 2 (table frame) make sense.
expanded (or x)
Toggles between regular and expanded format. When
expanded format is enabled, query results are
displayed in two columns, with the column name on
the left and the data on the right. This mode is
useful if the data wouldn't fit on the screen in
the normal ``horizontal'' mode.
Expanded mode is supported by all four output for-
mats.
null The second argument is a string that should be
printed whenever a column is null. The default is
not to print anything, which can easily be mis-
taken for, say, an empty string. Thus, one might
choose to write \pset null '(null)'.
fieldsep
Specifies the field separator to be used in
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unaligned output mode. That way one can create,
for example, tab- or comma-separated output, which
other programs might prefer. To set a tab as field
separator, type \pset fieldsep '\t'. The default
field separator is '|' (a vertical bar).
footer
Toggles the display of the default footer (x
rows).
numericlocale
Toggles the display of a locale-aware character to
separate groups of digits to the left of the
decimal marker. It also enables a locale-aware
decimal marker.
recordsep
Specifies the record (line) separator to use in
unaligned output mode. The default is a newline
character.
tuples_only (or t)
Toggles between tuples only and full display. Full
display may show extra information such as column
headers, titles, and various footers. In tuples
only mode, only actual table data is shown.
title [ text ]
Sets the table title for any subsequently printed
tables. This can be used to give your output
descriptive tags. If no argument is given, the
title is unset.
tableattr (or T) [ text ]
Allows you to specify any attributes to be placed
inside the HTML table tag. This could for example
be cellpadding or bgcolor. Note that you probably
don't want to specify border here, as that is
already taken care of by \pset border.
pager
Controls use of a pager for query and psql help
output. If the environment variable PAGER is set,
the output is piped to the specified program.
Otherwise a platform-dependent default (such as
more) is used.
When the pager is off, the pager is not used. When
the pager is on, the pager is used only when
appropriate, i.e. the output is to a terminal and
will not fit on the screen. (psql does not do a
perfect job of estimating when to use the pager.)
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\pset pager turns the pager on and off. Pager can
also be set to always, which causes the pager to
be always used.
Illustrations on how these different formats look can be
seen in the Examples [psql(1)] section.
Tip: There are various shortcut commands for \pset. See
\a, \C, \H, \t, \T, and \x.
Note: It is an error to call \pset without arguments.
In the future this call might show the current status
of all printing options.
q Quits the psql program.
qecho text [ ... ]
This command is identical to \echo except that the out-
put will be written to the query output channel, as set
by \o.
7 Resets (clears) the query buffer.
[ filename ]
Print or save the command line history to filename. If
filename is omitted, the history is written to the
standard output. This option is only available if psql
is configured to use the GNU Readline library.
t [ name [ value [ ... ] ] ]
Sets the internal variable name to value or, if more
than one value is given, to the concatenation of all of
them. If no second argument is given, the variable is
just set with no value. To unset a variable, use the
\unset command.
Valid variable names can contain characters, digits,
and underscores. See the section Variables [psql(1)]
below for details. Variable names are case-sensitive.
Although you are welcome to set any variable to any-
thing you want, psql treats several variables as spe-
cial. They are documented in the section about vari-
ables.
Note: This command is totally separate from the SQL
command SET [set(5)].
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Toggles the display of output column name headings and
row count footer. This command is equivalent to \pset
tuples_only and is provided for convenience.
T table_options
Allows you to specify attributes to be placed within
the table tag in HTML tabular output mode. This command
is equivalent to \pset tableattr table_options.
iming
Toggles a display of how long each SQL statement takes,
in milliseconds.
240 | |command}
Outputs the current query buffer to the file filename
or pipes it to the Unix command command.
Toggles expanded table formatting mode. As such it is
equivalent to \pset expanded.
[ pattern ]
Produces a list of all available tables, views and
sequences with their associated access privileges. If
a pattern is specified, only tables,views and sequences
whose names match the pattern are listed.
The GRANT [grant(5)] and REVOKE [revoke(5)] commands
are used to set access privileges.
This is an alias for \dp (``display privileges'').
[ command ]
Escapes to a separate Unix shell or executes the Unix
command command. The arguments are not further inter-
preted, the shell will see them as is.
? Shows help information about the backslash commands.
PATTERNS
The various \d commands accept a pattern parameter to
specify the object name(s) to be displayed. In the simplest
case, a pattern is just the exact name of the object. The
characters within a pattern are normally folded to lower
case, just as in SQL names; for example, \dt FOO will
display the table named foo. As in SQL names, placing double
quotes around a pattern stops folding to lower case. Should
you need to include an actual double quote character in a
pattern, write it as a pair of double quotes within a
double-quote sequence; again this is in accord with the
rules for SQL quoted identifiers. For example, \dt
"FOO""BAR" will display the table named FOO"BAR (not
foo"bar). Unlike the normal rules for SQL names, you can put
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double quotes around just part of a pattern, for instance
\dt FOO"FOO"BAR will display the table named fooFOObar.
Within a pattern, * matches any sequence of characters
(including no characters) and ? matches any single charac-
ter. (This notation is comparable to Unix shell file name
patterns.) For example, \dt int* displays all tables whose
names begin with int. But within double quotes, * and ? lose
these special meanings and are just matched literally.
A pattern that contains a dot (.) is interpreted as a schema
name pattern followed by an object name pattern. For exam-
ple, \dt foo*.bar* displays all tables whose table name
starts with bar that are in schemas whose schema name starts
with foo. When no dot appears, then the pattern matches only
objects that are visible in the current schema search path.
Again, a dot within double quotes loses its special meaning
and is matched literally.
Advanced users can use regular-expression notations such as
character classes, for example [0-9] to match any digit. All
regular expression special characters work as specified in
in the documentation, except for . which is taken as a
separator as mentioned above, * which is translated to the
regular-expression notation .*, and ? which is translated to
.. You can emulate these pattern characters at need by writ-
ing ? for ., (R+|) for R*, or (R|) for R?. Remember that
the pattern must match the whole name, unlike the usual
interpretation of regular expressions; write * at the begin-
ning 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 spe-
cial characters are matched literally in operator name pat-
terns (i.e., the argument of \do).
Whenever the pattern parameter is omitted completely, the \d
commands display all objects that are visible in the current
schema search path - this is equivalent to using the pattern
*. To see all objects in the database, use the pattern *.*.
ADVANCED FEATURES
VARIABLES
psql provides variable substitution features similar to com-
mon Unix command shells. Variables are simply name/value
pairs, where the value can be any string of any length. To
set variables, use the psql meta-command \set:
testdb=> \set foo bar
sets the variable foo to the value bar. To retrieve the con-
tent of the variable, precede the name with a colon and use
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it as the argument of any slash command:
testdb=> \echo :foo
bar
Note: The arguments of \set are subject to the same
substitution rules as with other commands. Thus you can
construct interesting references such as \set :foo
'something' and get ``soft links'' or ``variable vari-
ables'' of Perl or PHP fame, respectively. Unfor-
tunately (or fortunately?), there is no way to do any-
thing useful with these constructs. On the other hand,
\set bar :foo is a perfectly valid way to copy a vari-
able.
If you call \set without a second argument, the variable is
set, with an empty string as value. To unset (or delete) a
variable, use the command \unset.
psql's internal variable names can consist of letters,
numbers, and underscores in any order and any number of
them. A number of these variables are treated specially by
psql. They indicate certain option settings that can be
changed at run time by altering the value of the variable or
represent some state of the application. Although you can
use these variables for any other purpose, this is not
recommended, as the program behavior might grow really
strange really quickly. By convention, all specially treated
variables consist of all upper-case letters (and possibly
numbers and underscores). To ensure maximum compatibility in
the future, avoid using such variable names for your own
purposes. A list of all specially treated variables follows.
AUTOCOMMIT
When on (the default), each SQL command is automati-
cally 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 com-
mands are not committed until you explicitly issue COM-
MIT 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 com-
mand that cannot be executed inside a transaction block
(such as VACUUM).
Note: In autocommit-off mode, you must explicitly aban-
don any failed transaction by entering ABORT or ROLL-
BACK. Also keep in mind that if you exit the session
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without committing, your work will be lost.
Note: The autocommit-on mode is PostgreSQL's tradi-
tional behavior, but autocommit-off is closer to the
SQL spec. If you prefer autocommit-off, you may wish to
set it in the system-wide psqlrc file or your ~/.psqlrc
file.
DBNAME
The name of the database you are currently connected
to. This is set every time you connect to a database
(including program start-up), but can be unset.
ECHO If set to all, all lines entered from the keyboard or
from a script are written to the standard output before
they are parsed or executed. To select this behavior on
program start-up, use the switch -a. If set to queries,
psql merely prints all queries as they are sent to the
server. The switch for this is -e.
ECHO_HIDDEN
When this variable is set and a backslash command
queries the database, the query is first shown. This
way you can study the PostgreSQL internals and provide
similar functionality in your own programs. (To select
this behavior on program start-up, use the switch -E.)
If you set the variable to the value noexec, the
queries are just shown but are not actually sent to the
server and executed.
ENCODING
The current client character set encoding.
FETCH_COUNT
If this variable is set to an integer value > 0, the
results of SELECT queries are fetched and displayed in
groups of that many rows, rather than the default
behavior of collecting the entire result set before
display. Therefore only a limited amount of memory is
used, regardless of the size of the result set. Set-
tings of 100 to 1000 are commonly used when enabling
this feature. Keep in mind that when using this
feature, a query may 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 format-
ted separately, leading to varying column widths across
the row groups. The other output formats work better.
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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 exam-
ple, 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 ter-
minates. If the variable is set but has no numeric
value, the default is 10.
Note: This feature was shamelessly plagiarized from
Bash.
LASTOID
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The value of the last affected OID, as returned from an
INSERT or lo_insert command. This variable is only
guaranteed to be valid until after the result of the
next SQL command has been displayed.
ON_ERROR_ROLLBACK
When on, if a statement in a transaction block gen-
erates an error, the error is ignored and the transac-
tion continues. When interactive, such errors are only
ignored in interactive sessions, and not when reading
script files. When off (the default), a statement in a
transaction block that generates an error aborts the
entire transaction. The on_error_rollback-on mode works
by issuing an implicit SAVEPOINT for you, just before
each command that is in a transaction block, and rolls
back to the savepoint on error.
ON_ERROR_STOP
By default, if non-interactive scripts encounter an
error, such as a malformed SQL command or internal
meta-command, processing continues. This has been the
traditional behavior of psql but it is sometimes not
desirable. If this variable is set, script processing
will immediately terminate. If the script was called
from another script it will terminate in the same
fashion. If the outermost script was not called from an
interactive psql session but rather using the -f
option, psql will return error code 3, to distinguish
this case from fatal error conditions (error code 1).
PORT The database server port to which you are currently
connected. This is set every time you connect to a
database (including program start-up), but can be
unset.
PROMPT1
PROMPT2
PROMPT3
These specify what the prompts psql issues should look
like. See Prompting [psql(1)] below.
QUIET
This variable is equivalent to the command line option
-q. It is probably not too useful in interactive mode.
SINGLELINE
This variable is equivalent to the command line option
-S.
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SINGLESTEP
This variable is equivalent to the command line option
-s.
USER The database user you are currently connected as. This
is set every time you connect to a database (including
program start-up), but can be unset.
VERBOSITY
This variable can be set to the values default, ver-
bose, or terse to control the verbosity of error
reports.
SQL INTERPOLATION
An additional useful feature of psql variables is that you
can substitute (``interpolate'') them into regular SQL
statements. The syntax for this is again to prepend the
variable name with a colon (:).
testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;
would then query the table my_table. The value of the vari-
able is copied literally, so it can even contain unbalanced
quotes or backslash commands. You must make sure that it
makes sense where you put it. Variable interpolation will
not be performed into quoted SQL entities.
A popular application of this facility is to refer to the
last inserted OID in subsequent statements to build a
foreign key scenario. Another possible use of this mechanism
is to copy the contents of a file into a table column. First
load the file into a variable and then proceed as above.
testdb=> \set content '''' `cat my_file.txt` ''''
testdb=> INSERT INTO my_table VALUES (:content);
One problem with this approach is that my_file.txt might
contain single quotes. These need to be escaped so that they
don't cause a syntax error when the second line is pro-
cessed. This could be done with the program sed:
testdb=> \set content '''' `sed -e "s/'/''/g" < my_file.txt` ''''
If you are using non-standard-conforming strings then you'll
also need to double backslashes. This is a bit tricky:
testdb=> \set content '''' `sed -e "s/'/''/g" -e 's/\\/\\\\/g' < my_file.txt` ''''
Note the use of different shell quoting conventions so that
neither the single quote marks nor the backslashes are spe-
cial to the shell. Backslashes are still special to sed,
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however, so we need to double them. (Perhaps at one point
you thought it was great that all Unix commands use the same
escape character.)
Since colons may legally appear in SQL commands, the follow-
ing rule applies: the character sequence ``:name'' is not
changed unless ``name'' is the name of a variable that is
currently set. In any case you can escape a colon with a
backslash to protect it from substitution. (The colon syntax
for variables is standard SQL for embedded query languages,
such as ECPG. The colon syntax for array slices and type
casts are PostgreSQL extensions, hence the conflict.)
PROMPTING
The prompts psql issues can be customized to your prefer-
ence. The three variables PROMPT1, PROMPT2, and PROMPT3 con-
tain strings and special escape sequences that describe the
appearance of the prompt. Prompt 1 is the normal prompt that
is issued when psql requests a new command. Prompt 2 is
issued when more input is expected during command input
because the command was not terminated with a semicolon or a
quote was not closed. Prompt 3 is issued when you run an
SQL COPY command and you are expected to type in the row
values on the terminal.
The value of the selected prompt variable is printed
literally, except where a percent sign (%) is encountered.
Depending on the next character, certain other text is sub-
stituted 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 listen-
ing.
%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 #,
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otherwise a >. (The expansion of this value might
change during a database session as the result of the
command SET SESSION AUTHORIZATION.)
%R In prompt 1 normally =, but ^ if in single-line mode,
and ! if the session is disconnected from the database
(which can happen if \connect fails). In prompt 2 the
sequence is replaced by -, *, a single quote, a double
quote, or a dollar sign, depending on whether psql
expects more input because the command wasn't ter-
minated yet, because you are inside a /* ... */ com-
ment, or because you are inside a quoted or dollar-
escaped string. In prompt 3 the sequence doesn't pro-
duce anything.
%x Transaction status: an empty string when not in a tran-
saction 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 substi-
tuted.
%:name:
The value of the psql variable name. See the section
Variables [psql(1)] for details.
%`command`
The output of command, similar to ordinary ``back-
tick'' substitution.
%[ ... %]
Prompts may 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 Read-
line to work properly, these non-printing control char-
acters must be designated as invisible by surrounding
them with %[ and %]. Multiple pairs of these may 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.
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Note: This feature was shamelessly plagiarized from
tcsh.
COMMAND-LINE EDITING
psql supports the Readline library for convenient line edit-
ing and retrieval. The command history is automatically
saved when psql exits and is reloaded when psql starts up.
Tab-completion is also supported, although the completion
logic makes no claim to be an SQL parser. If for some reason
you do not like the tab completion, you can turn it off by
putting this in a file named .inputrc in your home direc-
tory:
$if psql
set disable-completion on
$endif
(This is not a psql but a Readline feature. Read its docu-
mentation for further details.)
ENVIRONMENT
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
Default connection database
PGHOST
PGPORT
PGUSER
Default connection parameters
PSQL_EDITOR
EDITOR
VISUAL
Editor used by the \e command. The variables are exam-
ined in the order listed; the first that is set is
used.
SHELL
Command executed by the \! command.
TMPDIR
Directory for storing temporary files. The default is
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/tmp.
This utility, like most other PostgreSQL utilities, also
uses the environment variables supported by libpq (see in
the documentation).
FILES
o Before starting up, psql attempts to read and execute com-
mands from the system-wide psqlrc file and the user's
~/.psqlrc file. (On Windows, the user's startup file is
named %APPDATA%\postgresql\psqlrc.conf.) See
PREFIX/share/psqlrc.sample for information on setting up
the system-wide file. It could be used to set up the
client or the server to taste (using the \set and SET com-
mands).
o Both the system-wide psqlrc file and the user's ~/.psqlrc
file can be made version-specific by appending a dash and
the PostgreSQL release number, for example ~/.psqlrc-
8.2.6. A matching version-specific file will be read in
preference to a non-version-specific file.
o The command-line history is stored in the file
~/.psql_history, or %APPDATA%\postgresql\psql_history on
Windows.
NOTES
o In an earlier life psql allowed the first argument of a
single-letter backslash command to start directly after
the command, without intervening whitespace. For compati-
bility this is still supported to some extent, but we are
not going to explain the details here as this use is
discouraged. If you get strange messages, keep this in
mind. For example
testdb=> \foo
Field separator is "oo".
which is perhaps not what one would expect.
o psql only works smoothly with servers of the same version.
That does not mean other combinations will fail outright,
but subtle and not-so-subtle problems might come up.
Backslash commands are particularly likely to fail if the
server is of a different version.
NOTES FOR WINDOWS USERS
psql is built as a ``console application''. Since the Win-
dows 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 con-
sole code page, it will warn you at startup. To change the
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PSQL(1) PostgreSQL Client Applications PSQL(1)
console code page, two things are necessary:
o 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.
o 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;
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PSQL(1) PostgreSQL Client Applications PSQL(1)
+-------+--------+
| 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 ]-
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first | 4
second | four
Application Last change: 2008-01-03 32
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