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man : 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 PostgreSQL, and see the query results. Alternatively,
input can be from a file. In addition, it provides a num-
ber of meta-commands and various shell-like features to
facilitate writing scripts and automating a wide variety
of tasks.
OPTIONS
-a
--echo-all
Print all input lines to standard output as they
are read. This is more useful for script processing
rather than interactive mode. This is equivalent to
setting the variable ECHO to all.
-A
--no-align
Switches to unaligned output mode. (The default
output mode is otherwise aligned.)
-c command
--command command
Specifies that psql is to execute one command
string, command, and then exit. This is useful in
shell scripts.
command must be either a command string that is
completely parsable by the server (i.e., it con-
tains no psql specific features), or a single back-
slash command. Thus you cannot mix SQL and psql
meta-commands. To achieve that, you could pipe the
string into psql, like this: echo "\x \\ select *
from foo;" | psql.
If the command string contains multiple SQL com-
mands, 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 stan-
dard output as well. This is equivalent to setting
the variable ECHO to queries.
-E
--echo-hidden
Echo the actual queries generated by \d and other
backslash commands. You can use this to study
psql's internal operations. This is equivalent to
setting the variable ECHO_HIDDEN from within psql.
-f filename
--file filename
Use the file filename as the source of commands
instead of reading commands interactively. After
the file is processed, psql terminates. This is in
many ways equivalent to the internal command \i.
If filename is - (hyphen), then standard input is
read.
Using this option is subtly different from writing
psql < filename. In general, both will do what you
expect, but using -f enables some nice features
such as error messages with line numbers. There is
also a slight chance that using this option will
reduce the start-up overhead. On the other hand,
the variant using the shell's input redirection is
(in theory) guaranteed to yield exactly the same
output that you would have gotten had you entered
everything by hand.
-F separator
--field-separator separator
Use separator as the field separator for unaligned
output. This is equivalent to \pset fieldsep or \f.
-h hostname
--host hostname
Specifies the host name of the machine on which the
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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 addi-
tion 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 lis-
tening for connections. Defaults to the value of
the PGPORT environment variable or, if not set, to
the port specified at compile time, usually 5432.
-P assignment
--pset assignment
Allows you to specify printing options in the style
of \pset on the command line. Note that here you
have to separate name and value with an equal sign
instead of a space. Thus to set the output format
to LaTeX, you could write -P format=latex.
-q
--quiet
Specifies that psql should do its work quietly. By
default, it prints welcome messages and various
informational output. If this option is used, none
of this happens. This is useful with the -c option.
Within psql you can also set the QUIET variable to
achieve the same effect.
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-R separator
--record-separator separator
Use separator as the record separator for unaligned
output. This is equivalent to the \pset recordsep
command.
-s
--single-step
Run in single-step mode. That means the user is
prompted before each command is sent to the server,
with the option to cancel execution as well. Use
this to debug scripts.
-S
--single-line
Runs in single-line mode where a newline terminates
an SQL command, as a semicolon does.
Note: This mode is provided for those who insist on
it, but you are not necessarily encouraged to use
it. In particular, if you mix SQL and meta-commands
on a line the order of execution might not always
be clear to the inexperienced user.
-t
--tuples-only
Turn off printing of column names and result row
count footers, etc. This is equivalent to the \t
command.
-T table_options
--table-attr table_options
Allows you to specify options to be placed within
the HTML table tag. See \pset for details.
-u Forces psql to prompt for the user name and pass-
word 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.
-U username
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--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 inter-
nal command. Note that you must separate name and
value, if any, by an equal sign on the command
line. To unset a variable, leave off the equal
sign. To just set a variable without a value, use
the equal sign but leave off the value. These
assignments are done during a very early stage of
start-up, so variables reserved for internal pur-
poses might get overwritten later.
-V
--version
Print the psql version and exit.
-W
--password
Forces psql to prompt for a password before con-
necting to a database.
psql should automatically prompt for a password
whenever the server requests password authentica-
tion. However, currently password request detec-
tion 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,
--no-psqlrc
Do not read the start-up file (neither the system-
wide psqlrc file nor the user's ~/.psqlrc file).
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-?
--help Show help about psql command line arguments, and
exit.
EXIT STATUS
psql returns 0 to the shell if it finished normally, 1 if
a fatal error of its own (out of memory, file not found)
occurs, 2 if the connection to the server went bad and the
session was not interactive, and 3 if an error occurred in
a script and the variable ON_ERROR_STOP was set.
USAGE
CONNECTING TO A DATABASE
psql is a regular PostgreSQL client application. In order
to connect to a database you need to know the name of your
target database, the host name and port number of the
server and what user name you want to connect as. psql can
be told about those parameters via command line options,
namely -d, -h, -p, and -U respectively. If an argument is
found that does not belong to any option it will be inter-
preted 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 administrator should have
informed you about your access rights.
When the defaults aren't quite right, you can save your-
self some typing by setting the environment variables
PGDATABASE, PGHOST, PGPORT and/or PGUSER to appropriate
values. (For additional environment variables, see the
documentation.) It is also convenient to have a ~/.pgpass
file to avoid regularly having to type in passwords. See
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 termi-
nate.
ENTERING SQL COMMANDS
In normal operation, psql provides a prompt with the name
of the database to which psql is currently connected, fol-
lowed by the string =>. For example,
$ psql testdb
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Welcome to psql 8.1.0, 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 sev-
eral lines for clarity. If the command was sent and exe-
cuted without error, the results of the command are dis-
played on the screen.
Whenever a command is executed, psql also polls for asyn-
chronous notification events generated by LISTEN [lis-
ten(7)] and NOTIFY [notify(7)].
META-COMMANDS
Anything you enter in psql that begins with an unquoted
backslash is a psql meta-command that is processed by psql
itself. These commands help make psql more useful for
administration or scripting. Meta-commands are more com-
monly called slash or backslash commands.
The format of a psql command is the backslash, followed
immediately by a command verb, then any arguments. The
arguments are separated from the command verb and each
other by any number of whitespace characters.
To include whitespace into an argument you may quote it
with a single quote. To include a single quote into such
an argument, precede it by a backslash. Anything contained
in single quotes is furthermore subject to C-like substi-
tutions for \n (new line), \t (tab), \digits (octal), and
\xdigits (hexadecimal).
If an unquoted argument begins with a colon (:), it is
taken as a psql variable and the value of the variable is
used as the argument instead.
Arguments that are enclosed in backquotes (`) are taken as
a command line that is passed to the shell. The output of
the command (with any trailing newline removed) is taken
as the argument value. The above escape sequences also
apply in backquotes.
Some commands take an SQL identifier (such as a table
name) as argument. These arguments follow the syntax rules
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of SQL: Unquoted letters are forced to lowercase, while
double quotes (") protect letters from case conversion and
allow incorporation of whitespace into the identifier.
Within double quotes, paired double quotes reduce to a
single double quote in the resulting name. For example,
FOO"BAR"BAZ is interpreted as fooBARbaz, and "A weird""
name" becomes A weird" name.
Parsing for arguments stops when another unquoted back-
slash 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 com-
mands, if any. That way SQL and psql commands can be
freely mixed on a line. But in any case, the arguments of
a meta-command cannot continue beyond the end of the line.
The following meta-commands are defined:
\a If the current table output format is unaligned, it
is switched to aligned. If it is not unaligned, it
is set to unaligned. This command is kept for back-
wards compatibility. See \pset for a more general
solution.
\cd [ directory ]
Changes the current working directory to directory.
Without argument, changes to the current user's
home directory.
Tip: To print your current working directory, use
\!pwd.
\C [ title ]
Sets the title of any tables being printed as the
result of a query or unset any such title. This
command is equivalent to \pset title title. (The
name of this command derives from ``caption'', as
it was previously only used to set the caption in
an HTML table.)
\connect (or \c) [ dbname [ username ] ]
Establishes a connection to a new database and/or
under a user name. The previous connection is
closed. If dbname is - the current database name is
assumed.
If username is omitted the current user name is
assumed.
As a special rule, \connect without any arguments
will connect to the default database as the default
user (as you would have gotten by starting psql
without any arguments).
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If the connection attempt failed (wrong user name,
access denied, etc.), the previous connection will
be kept if and only if psql is in interactive mode.
When executing a non-interactive script, processing
will immediately stop with an error. This distinc-
tion was chosen as a user convenience against typos
on the one hand, and a safety mechanism that
scripts are not accidentally acting on the wrong
database on the other hand.
\copy table
Performs a frontend (client) copy. This is an oper-
ation that runs an SQL COPY [copy(7)] command, but
instead of the server reading or writing the speci-
fied file, psql reads or writes the file and routes
the data between the server and the local file sys-
tem. This means that file accessibility and privi-
leges are those of the local user, not the server,
and no SQL superuser privileges are required.
The syntax of the command is similar to that of the
SQL COPY [copy(7)] command. Note that, because of
this, special parsing rules apply to the \copy com-
mand. In particular, the variable substitution
rules and backslash escapes do not apply.
\copy table from stdin | stdout reads/writes based
on the command input and output respectively. All
rows are read from the same source that issued the
command, continuing until \. is read or the stream
reaches EOF. Output is sent to the same place as
command output. To read/write from psql's standard
input or output, use pstdin or pstdout. This option
is useful for populating tables in-line within a
SQL script file.
Tip: This operation is not as efficient as the SQL
COPY command because all data must pass through the
client/server connection. For large amounts of data
the SQL command may be preferable.
\copyright
Shows the copyright and distribution terms of Post-
greSQL.
\d [ pattern ]
\d+ [ pattern ]
For each relation (table, view, index, or sequence)
matching the pattern, show all columns, their
types, the tablespace (if not the default) and any
special attributes such as NOT NULL or defaults, if
any. Associated indexes, constraints, rules, and
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triggers are also shown, as is the view definition
if the relation is a view. (``Matching the pat-
tern'' 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
convenience measure.
\da [ pattern ]
Lists all available aggregate functions, together
with the data type they operate on. If pattern is
specified, only aggregates whose names match the
pattern are shown.
\db [ pattern ]
\db+ [ pattern ]
Lists all available tablespaces. If pattern is
specified, only tablespaces whose names match the
pattern are shown. If + is appended to the command
name, each object is listed with its associated
permissions.
\dc [ pattern ]
Lists all available conversions between character-
set encodings. If pattern is specified, only con-
versions whose names match the pattern are listed.
\dC Lists all available type casts.
\dd [ pattern ]
Shows the descriptions of objects matching the pat-
tern, or of all visible objects if no argument is
given. But in either case, only objects that have a
description are listed. (``Object'' covers aggre-
gates, 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)
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Descriptions for objects can be created with the
COMMENT [comment(7)] SQL command.
\dD [ pattern ]
Lists all available domains. If pattern is speci-
fied, only matching domains are shown.
\df [ pattern ]
\df+ [ pattern ]
Lists available functions, together with their
argument and return types. If pattern is specified,
only functions whose names match the pattern are
shown. If the form \df+ is used, additional infor-
mation 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 func-
tions that accept or return type cstring.
\dg [ pattern ]
Lists all database roles. If pattern is specified,
only those roles whose names match the pattern are
listed. (This command is now effectively the same
as \du.)
\distvS [ 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.
\dl This is an alias for \lo_list, which shows a list
of large objects.
\dn [ pattern ]
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\dn+ [ pattern ]
Lists all available schemas (namespaces). If pat-
tern (a regular expression) is specified, only
schemas whose names match the pattern are listed.
Non-local temporary schemas are suppressed. If + is
appended to the command name, each object is listed
with its associated permissions and description, if
any.
\do [ pattern ]
Lists available operators with their operand and
return types. If pattern is specified, only opera-
tors whose names match the pattern are listed.
\dp [ 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 commands GRANT and REVOKE are used to set
access privileges. See GRANT [grant(7)] for more
information.
\dT [ pattern ]
\dT+ [ pattern ]
Lists all data types or only those that match pat-
tern. The command form \dT+ shows extra informa-
tion.
\du [ pattern ]
Lists all database roles, or only those that match
pattern.
\edit (or \e) [ filename ]
If filename is specified, the file is edited; after
the editor exits, its content is copied back to the
query buffer. If no argument is given, the current
query buffer is copied to a temporary file which is
then edited in the same fashion.
The new query buffer is then re-parsed according to
the normal rules of psql, where the whole buffer is
treated as a single line. (Thus you cannot make
scripts this way. Use \i for that.) This means also
that if the query ends with (or rather contains) a
semicolon, it is immediately executed. In other
cases it will merely wait in the query buffer.
Tip: psql searches the environment variables
PSQL_EDITOR, EDITOR, and VISUAL (in that order) for
an editor to use. If all of them are unset, vi is
used on Unix systems, notepad.exe on Windows
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systems.
\echo text [ ... ]
Prints the arguments to the standard output, sepa-
rated 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 trail-
ing 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 command.
\encoding [ encoding ]
Sets the client character set encoding. Without an
argument, this command shows the current encoding.
\f [ string ]
Sets the field separator for unaligned query out-
put. The default is the vertical bar (|). See also
\pset for a generic way of setting output options.
\g [ { filename | |command } ]
Sends the current query input buffer to the server
and optionally stores the query's output in file-
name or pipes the output into a separate Unix shell
executing command. A bare \g is virtually equiva-
lent to a semicolon. A \g with argument is a ``one-
shot'' alternative to the \o command.
\help (or \h) [ command ]
Gives syntax help on the specified SQL command. If
command is not specified, then psql will list all
the commands for which syntax help is available. If
command is an asterisk (*), then syntax help on all
SQL commands is shown.
Note: To simplify typing, commands that consists of
several words do not have to be quoted. Thus it is
fine to type \help alter table.
\H Turns on HTML query output format. If the HTML for-
mat 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.
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\i filename
Reads input from the file filename and executes it
as though it had been typed on the keyboard.
Note: If you want to see the lines on the screen as
they are read you must set the variable ECHO to
all.
\l (or \list)
\l+ (or \list+)
List the names, owners, and character set encodings
of all the databases in the server. If + is
appended to the command name, database descriptions
are also displayed.
\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 one ought to remem-
ber if one wants to access the object ever again.
For that reason it is recommended to always associ-
ate 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.
\lo_list
Shows a list of all PostgreSQL large objects cur-
rently stored in the database, along with any com-
ments provided for them.
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\lo_unlink loid
Deletes the large object with OID loid from the
database.
Tip: Use \lo_list to find out the large object's
OID.
\o [ {filename | |command} ]
Saves future query results to the file filename or
pipes future results into a separate Unix shell to
execute command. If no arguments are specified, the
query output will be reset to the standard output.
``Query results'' includes all tables, command
responses, and notices obtained from the database
server, as well as output of various backslash com-
mands that query the database (such as \d), but not
error messages.
Tip: To intersperse text output in between query
results, use \qecho.
\p Print the current query buffer to the standard out-
put.
\pset parameter [ value ]
This command sets options affecting the output of
query result tables. parameter describes which
option is to be set. The semantics of value depend
thereon.
Adjustable printing options are:
format Sets the output format to one of unaligned,
aligned, html, latex, or troff-ms. Unique
abbreviations are allowed. (That would mean
one letter is enough.)
``Unaligned'' writes all columns of a row on
a line, separated by the currently active
field separator. This is intended to create
output that might be intended to be read in
by other programs (tab-separated, comma-sep-
arated). ``Aligned'' mode is the standard,
human-readable, nicely formatted 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 doc-
uments! (This might not be so dramatic in
HTML, but in LaTeX you must have a complete
document wrapper.)
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border The second argument must be a number. In
general, the higher the number the more bor-
ders and lines the tables will have, but
this depends on the particular format. In
HTML mode, this will translate directly into
the border=... attribute, in the others only
values 0 (no border), 1 (internal dividing
lines), and 2 (table frame) make sense.
expanded (or x)
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 out-
put formats.
null The second argument is a string that should
be printed whenever a column is null. The
default is not to print anything, which can
easily be mistaken for, say, an empty
string. Thus, one might choose to write
\pset null '(null)'.
fieldsep
Specifies the field separator to be used in
unaligned output mode. That way one can cre-
ate, 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 char-
acter 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 dis-
play. Full display may show extra
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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 bor-
der 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.) \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 argu-
ments. In the future this call might show the cur-
rent status of all printing options.
\q Quits the psql program.
\qecho text [ ... ]
This command is identical to \echo except that the
output will be written to the query output channel,
as set by \o.
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\r Resets (clears) the query buffer.
\s [ filename ]
Print or save the command line history to filename.
If filename is omitted, the history is written to
the standard output. This option is only available
if psql is configured to use the GNU Readline
library.
Note: In the current version, it is no longer nec-
essary to save the command history, since that will
be done automatically on program termination. The
history is also loaded automatically every time
psql starts up.
\set [ name [ value [ ... ] ] ]
Sets the internal variable name to value or, if
more than one value is given, to the concatenation
of all of them. If no second argument is given, the
variable is just set with no value. To unset a
variable, use the \unset command.
Valid variable names can contain characters, dig-
its, and underscores. See the section Variables
[psql(1)] below for details. Variable names are
case-sensitive.
Although you are welcome to set any variable to
anything you want, psql treats several variables as
special. They are documented in the section about
variables.
Note: This command is totally separate from the SQL
command SET [set(7)].
\t Toggles the display of output column name headings
and row count footer. This command is equivalent to
\pset tuples_only and is provided for convenience.
\T table_options
Allows you to specify attributes to be placed
within the table tag in HTML tabular output mode.
This command is equivalent to \pset tableattr
table_options.
\timing
Toggles a display of how long each SQL statement
takes, in milliseconds.
\w {filename | |command}
Outputs the current query buffer to the file file-
name or pipes it to the Unix command command.
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\x Toggles expanded table formatting mode. As such it
is equivalent to \pset expanded.
\z [ pattern ]
Produces a list of all available tables, views and
sequences with their associated access privileges.
If a pattern is specified, only tables,views and
sequences whose names match the pattern are listed.
The commands GRANT and REVOKE are used to set
access privileges. See GRANT [grant(7)] for more
information.
This is an alias for \dp (``display privileges'').
\! [ command ]
Escapes to a separate Unix shell or executes the
Unix command command. The arguments are not further
interpreted, the shell will see them as is.
\? Shows help information about the backslash com-
mands.
The various \d commands accept a pattern parameter to
specify the object name(s) to be displayed. * means ``any
sequence of characters'' and ? means ``any single charac-
ter''. (This notation is comparable to Unix shell file
name patterns.) Advanced users can also use regular-
expression notations such as character classes, for exam-
ple [0-9] to match ``any digit''. To make any of these
pattern-matching characters be interpreted literally, sur-
round it with double quotes.
A pattern that contains an (unquoted) dot is interpreted
as a schema name pattern followed by an object name pat-
tern. For example, \dt foo*.bar* displays all tables in
schemas whose name starts with foo and whose table name
starts with bar. If no dot appears, then the pattern
matches only objects that are visible in the current
schema search path.
Whenever the pattern parameter is omitted completely, the
\d commands display all objects that are visible in the
current schema search path. To see all objects in the
database, use the pattern *.*.
ADVANCED FEATURES
VARIABLES
psql provides variable substitution features similar to
common Unix command shells. Variables are simply
name/value pairs, where the value can be any string of any
length. To set variables, use the psql meta-command \set:
Application 2005-11-05 19
PSQL(1) PostgreSQL Client Applications PSQL(1)
testdb=> \set foo bar
sets the variable foo to the value bar. To retrieve the
content of the variable, precede the name with a colon and
use it as the argument of any slash command:
testdb=> \echo :foo
bar
Note: The arguments of \set are subject to the same
substitution rules as with other commands. Thus you
can construct interesting references such as \set
:foo 'something' and get ``soft links'' or ``vari-
able variables'' of Perl or PHP fame, respectively.
Unfortunately (or fortunately?), there is no way to
do anything useful with these constructs. On the
other hand, \set bar :foo is a perfectly valid way
to copy a variable.
If you call \set without a second argument, the variable
is set, with an empty string as value. To unset (or
delete) a variable, use the command \unset.
psql's internal variable names can consist of letters,
numbers, and underscores in any order and any number of
them. A number of these variables are treated specially by
psql. They indicate certain option settings that can be
changed at run time by altering the value of the variable
or represent some state of the application. Although you
can use these variables for any other purpose, this is not
recommended, as the program behavior might grow really
strange really quickly. By convention, all specially
treated variables consist of all upper-case letters (and
possibly numbers and underscores). To ensure maximum com-
patibility 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 automat-
ically 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).
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PSQL(1) PostgreSQL Client Applications PSQL(1)
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 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 con-
nected 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.
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 match-
ing 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.
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HISTFILE
The file name that will be used to store the his-
tory 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 his-
tory. The default value is 500.
Note: This feature was shamelessly plagiarized from
Bash.
HOST The database server host you are currently con-
nected 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 Con-
trol+D) to an interactive session of psql will ter-
minate the application. If set to a numeric value,
that many EOF characters are ignored before the
application terminates. If the variable is set but
has no numeric value, the default is 10.
Note: This feature was shamelessly plagiarized from
Bash.
LASTOID
The value of the last affected OID, as returned
from an INSERT or lo_insert command. This variable
is only guaranteed to be valid until after the
result of the next SQL command has been displayed.
ON_ERROR_ROLLBACK
When on, if a statement in a transaction block gen-
erates an error, the error is ignored and the
transaction continues. When interactive, such
errors are only ignored in interactive sessions,
and not when reading script files. When off (the
default), a statement in a transaction block that
generates an error aborts the entire transaction.
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PSQL(1) PostgreSQL Client Applications PSQL(1)
The on_error_rollback-on mode works by issuing an
implicit SAVEPOINT for you, just before each com-
mand 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 some-
times 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 ses-
sion 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 inter-
active mode.
SINGLELINE
This variable is equivalent to the command line
option -S.
SINGLESTEP
This variable is equivalent to the command line
option -s.
USER The database user you are currently connected as.
This is set every time you connect to a database
(including program start-up), but can be unset.
VERBOSITY
This variable can be set to the values default,
verbose, or terse to control the verbosity of error
reports.
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SQL INTERPOLATION
An additional useful feature of psql variables is that you
can substitute (``interpolate'') them into regular SQL
statements. The syntax for this is again to prepend the
variable name with a colon (:).
testdb=> \set foo 'my_table'
testdb=> SELECT * FROM :foo;
would then query the table my_table. The value of the
variable is copied literally, so it can even contain
unbalanced quotes or backslash commands. You must make
sure that it makes sense where you put it. Variable inter-
polation 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 for-
eign 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 possible problem with this approach is that
my_file.txt might contain single quotes. These need to be
escaped so that they don't cause a syntax error when the
second line is processed. This could be done with the pro-
gram sed:
testdb=> \set content '\'' `sed -e "s/'/\\\\\\'/g" < my_file.txt` '\''
Observe the correct number of backslashes (6)! It works
this way: After psql has parsed this line, it passes sed
-e "s/'/\\\'/g" < my_file.txt to the shell. The shell will
do its own thing inside the double quotes and execute sed
with the arguments -e and s/'/\\'/g. When sed parses this
it will replace the two backslashes with a single one and
then do the substitution. Perhaps at one point you thought
it was great that all Unix commands use the same escape
character. And this is ignoring the fact that you might
have to escape all backslashes as well because SQL text
constants are also subject to certain interpretations. In
that case you might be better off preparing the file
externally.
Since colons may legally appear in SQL commands, the fol-
lowing 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
Application 2005-11-05 24
PSQL(1) PostgreSQL Client Applications PSQL(1)
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
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 com-
mand 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 lit-
erally, 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 AUTHORIZA-
TION.)
%/ The name of the current database.
%~ Like %/, but the output is ~ (tilde) if the
database is your default database.
%# If the session user is a database superuser, then a
#, otherwise a >. (The expansion of this value
might change during a database session as the
result of the command SET SESSION AUTHORIZATION.)
%R In prompt 1 normally =, but ^ if in single-line
mode, and ! if the session is disconnected from the
database (which can happen if \connect fails). In
prompt 2 the sequence is replaced by -, *, a single
quote, a double quote, or a dollar sign, depending
on whether psql expects more input because the
Application 2005-11-05 25
PSQL(1) PostgreSQL Client Applications PSQL(1)
command wasn't terminated yet, because you are
inside a /* ... */ comment, or because you are
inside a quoted or dollar-escaped string. In prompt
3 the sequence doesn't produce anything.
%x Transaction status: an empty string when not in a
transaction block, or * when in a transaction
block, or ! when in a failed transaction block, or
? when the transaction state is indeterminate (for
example, because there is no connection).
%digits
The character with the indicated octal code is sub-
stituted.
%:name:
The value of the psql variable name. See the sec-
tion 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 Readline to work properly, these non-
printing control characters must be designated as
invisible by surrounding them with %[ and %]. Mul-
tiple 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 termi-
nals.
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 automati-
cally 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
Application 2005-11-05 26
PSQL(1) PostgreSQL Client Applications PSQL(1)
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 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
examined in the order listed; the first that is set
is used.
SHELL Command executed by the \! command.
TMPDIR Directory for storing temporary files. The default
is /tmp.
FILES
o Before starting up, psql attempts to read and execute
commands from the system-wide psqlrc file and the user's
~/.psqlrc file. (On Windows, the user's startup file is
named %APPDATA%\postgresql\psqlrc.conf.) See PRE-
FIX/share/psqlrc.sample for information on setting up
the system-wide file. It could be used to set up the
client or the server to taste (using the \set and SET
commands).
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-8.1.0. A matching version-specific file will
Application 2005-11-05 27
PSQL(1) PostgreSQL Client Applications PSQL(1)
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 compat-
ibility 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 ver-
sion. 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 problem-
atic console code page, it will warn you at startup. To
change the 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 sev-
eral 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:
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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
Application 2005-11-05 29
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Output format is unaligned.
peter@localhost testdb=> \pset fieldsep ","
Field separator is ",".
peter@localhost testdb=> \pset tuples_only
Showing only tuples.
peter@localhost testdb=> SELECT second, first FROM my_table;
one,1
two,2
three,3
four,4
Alternatively, use the short commands:
peter@localhost testdb=> \a \t \x
Output format is aligned.
Tuples only is off.
Expanded display is on.
peter@localhost testdb=> SELECT * FROM my_table;
-[ RECORD 1 ]-
first | 1
second | one
-[ RECORD 2 ]-
first | 2
second | two
-[ RECORD 3 ]-
first | 3
second | three
-[ RECORD 4 ]-
first | 4
second | four
SEE ALSO
Environment Variables (the documentation)
Application 2005-11-05 30
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