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 number of meta-commands and various shell-like features
to facilitate writing scripts and automating a wide variety of tasks.
OPTIONS
-a
--echo-all
Print all input lines to standard output as they are read. This is more useful for script processing rather than interactive mode.
This is equivalent to setting the variable ECHO to all.
-A
--no-align
Switches to unaligned output mode. (The default output mode is otherwise aligned.)
-c command
--command command
Specifies that psql is to execute one command string, command, and then exit. This is useful in shell scripts.
command must be either a command string that is completely parsable by the server (i.e., it contains no psql specific features), or
a single backslash command. Thus you cannot mix SQL and psql meta-commands with this option. To achieve that, you could pipe the
string into psql, like this: echo 'x \ SELECT * FROM foo;' | psql. (\ is the separator meta-command.)
If the command string contains multiple SQL commands, they are processed in a single transaction, unless there are explicit
BEGIN/COMMIT commands included in the string to divide it into multiple transactions. This is different from the behavior when the
same string is fed to psql's standard input.
-d dbname
--dbname dbname
Specifies the name of the database to connect to. This is equivalent to specifying dbname as the first non-option argument on the
command line.
If this parameter contains an = sign, it is treated as a conninfo string. See in the documentation for more information.
-e
--echo-queries
Copy all SQL commands sent to the server to standard output as well. This is equivalent to setting the variable ECHO to queries.
-E
--echo-hidden
Echo the actual queries generated by d and other backslash commands. You can use this to study psql's internal operations. This is
equivalent to setting the variable ECHO_HIDDEN from within psql.
-f filename
--file filename
Use the file filename as the source of commands instead of reading commands interactively. After the file is processed, psql termi-
nates. This is in many ways equivalent to the internal command i.
If filename is - (hyphen), then standard input is read.
Using this option is subtly different from writing psql < filename. In general, both will do what you expect, but using -f enables
some nice features such as error messages with line numbers. There is also a slight chance that using this option will reduce the
start-up overhead. On the other hand, the variant using the shell's input redirection is (in theory) guaranteed to yield exactly the
same output that you would have gotten had you entered everything by hand.
-F separator
--field-separator separator
Use separator as the field separator for unaligned output. This is equivalent to pset fieldsep or f.
-h hostname
--host hostname
Specifies the host name of the machine on which the server is running. If the value begins with a slash, it is used as the directory
for the Unix-domain socket.
-H
--html Turn on HTML tabular output. This is equivalent to pset format html or the H command.
-l
--list List all available databases, then exit. Other non-connection options are ignored. This is similar to the internal command list.
-L filename
--log-file filename
Write all query output into file filename, in addition to the normal output destination.
-n
--no-readline
Do not use readline for line editing and do not use the history. This can be useful to turn off tab expansion when cutting and
pasting.
-o filename
--output filename
Put all query output into file filename. This is equivalent to the command o.
-p port
--port port
Specifies the TCP port or the local Unix-domain socket file extension on which the server is listening for connections. Defaults to
the value of the PGPORT environment variable or, if not set, to the port specified at compile time, usually 5432.
-P assignment
--pset assignment
Allows you to specify printing options in the style of pset on the command line. Note that here you have to separate name and value
with an equal sign instead of a space. Thus to set the output format to LaTeX, you could write -P format=latex.
-q
--quiet
Specifies that psql should do its work quietly. By default, it prints welcome messages and various informational output. If this
option is used, none of this happens. This is useful with the -c option. Within psql you can also set the QUIET variable to achieve
the same effect.
-R separator
--record-separator separator
Use separator as the record separator for unaligned output. This is equivalent to the pset recordsep command.
-s
--single-step
Run in single-step mode. That means the user is prompted before each command is sent to the server, with the option to cancel execu-
tion 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 command.
-T table_options
--table-attr table_options
Allows you to specify options to be placed within the HTML table tag. See pset for details.
-U username
--username username
Connect to the database as the user username instead of the default. (You must have permission to do so, of course.)
-v assignment
--set assignment
--variable assignment
Perform a variable assignment, like the set internal command. Note that you must separate name and value, if any, by an equal sign
on the command line. To unset a variable, leave off the equal sign. To just set a variable without a value, use the equal sign but
leave off the value. These assignments are done during a very early stage of start-up, so variables reserved for internal purposes
might get overwritten later.
-V
--version
Print the psql version and exit.
-w
--no-password
Never issue a password prompt. If the server requires password authentication and a password is not available by other means such as
a .pgpass file, the connection attempt will fail. This option can be useful in batch jobs and scripts where no user is present to
enter a password.
Note that this option will remain set for the entire session, and so it affects uses of the meta-command connect as well as the
initial connection attempt.
-W
--password
Force psql to prompt for a password before connecting to a database.
This option is never essential, since psql will automatically prompt for a password if the server demands password authentication.
However, psql will waste a connection attempt finding out that the server wants a password. In some cases it is worth typing -W to
avoid the extra connection attempt.
Note that this option will remain set for the entire session, and so it affects uses of the meta-command connect as well as the
initial connection attempt.
-x
--expanded
Turn on the expanded table formatting mode. This is equivalent to the x command.
-X,
--no-psqlrc
Do not read the start-up file (neither the system-wide psqlrc file nor the user's ~/.psqlrc file).
-1
--single-transaction
When psql executes a script with the -f option, adding this option wraps BEGIN/COMMIT around the script to execute it as a single
transaction. This ensures that either all the commands complete successfully, or no changes are applied.
If the script itself uses BEGIN, COMMIT, or ROLLBACK, this option will not have the desired effects. Also, if the script contains
any command that cannot be executed inside a transaction block, specifying this option will cause that command (and hence the whole
transaction) to fail.
-?
--help Show help about psql command line arguments, and exit.
EXIT STATUS
psql returns 0 to the shell if it finished normally, 1 if a fatal error of its own (out of memory, file not found) occurs, 2 if the connec-
tion to the server went bad and the session was not interactive, and 3 if an error occurred in a script and the variable ON_ERROR_STOP was
set.
USAGE
CONNECTING TO A DATABASE
psql is a regular PostgreSQL client application. In order to connect to a database you need to know the name of your target database, the
host name and port number of the server and what user name you want to connect as. psql can be told about those parameters via command line
options, namely -d, -h, -p, and -U respectively. If an argument is found that does not belong to any option it will be interpreted as the
database name (or the user name, if the database name is already given). Not all these options are required; there are useful defaults. If
you omit the host name, psql will connect via a Unix-domain socket to a server on the local host, or via TCP/IP to localhost on machines
that don't have Unix-domain sockets. The default port number is determined at compile time. Since the database server uses the same
default, you will not have to specify the port in most cases. The default user name is your Unix user name, as is the default database
name. Note that you cannot just connect to any database under any user name. Your database administrator should have informed you about
your access rights.
When the defaults aren't quite right, you can save yourself some typing by setting the environment variables PGDATABASE, PGHOST, PGPORT
and/or PGUSER to appropriate values. (For additional environment variables, see in the documentation.) It is also convenient to have a
~/.pgpass file to avoid regularly having to type in passwords. See in the documentation for more information.
An alternative way to specify connection parameters is in a conninfo string, which is used instead of a database name. This mechanism give
you very wide control over the connection. For example:
$ psql "service=myservice sslmode=require"
This way you can also use LDAP for connection parameter lookup as described in in the documentation. See in the documentation for more
information on all the available connection options.
If the connection could not be made for any reason (e.g., insufficient privileges, server is not running on the targeted host, etc.), psql
will return an error and terminate.
ENTERING SQL COMMANDS
In normal operation, psql provides a prompt with the name of the database to which psql is currently connected, followed by the string =>.
For example:
$ psql testdb
psql (8.4.4)
Type "help" for help.
testdb=>
At the prompt, the user can type in SQL commands. Ordinarily, input lines are sent to the server when a command-terminating semicolon is
reached. An end of line does not terminate a command. Thus commands can be spread over several lines for clarity. If the command was sent
and executed without error, the results of the command are displayed on the screen.
Whenever a command is executed, psql also polls for asynchronous notification events generated by LISTEN [listen(7)] and NOTIFY
[notify(7)].
META-COMMANDS
Anything you enter in psql that begins with an unquoted backslash is a psql meta-command that is processed by psql itself. These commands
help make psql more useful for administration or scripting. Meta-commands are more commonly called slash or backslash commands.
The format of a psql command is the backslash, followed immediately by a command verb, then any arguments. The arguments are separated from
the command verb and each other by any number of whitespace characters.
To include whitespace into an argument you can quote it with a single quote. To include a single quote into such an argument, use two sin-
gle quotes. Anything contained in single quotes is furthermore subject to C-like substitutions for
(new line), (tab), digits
(octal), and xdigits (hexadecimal).
If an unquoted argument begins with a colon (:), it is taken as a psql variable and the value of the variable is used as the argument
instead.
Arguments that are enclosed in backquotes (`) are taken as a command line that is passed to the shell. The output of the command (with any
trailing newline removed) is taken as the argument value. The above escape sequences also apply in backquotes.
Some commands take an SQL identifier (such as a table name) as argument. These arguments follow the syntax rules of SQL: Unquoted letters
are forced to lowercase, while double quotes (") protect letters from case conversion and allow incorporation of whitespace into the iden-
tifier. Within double quotes, paired double quotes reduce to a single double quote in the resulting name. For example, FOO"BAR"BAZ is
interpreted as fooBARbaz, and "A weird"" name" becomes A weird" name.
Parsing for arguments stops when another unquoted backslash occurs. This is taken as the beginning of a new meta-command. The special
sequence \ (two backslashes) marks the end of arguments and continues parsing SQL commands, if any. That way SQL and psql commands can be
freely mixed on a line. But in any case, the arguments of a meta-command cannot continue beyond the end of the line.
The following meta-commands are defined:
a If the current table output format is unaligned, it is switched to aligned. If it is not unaligned, it is set to unaligned. This
command is kept for backwards compatibility. See pset for a more general solution.
cd [ directory ]
Changes the current working directory to directory. Without argument, changes to the current user's home directory.
Tip: To print your current working directory, use ! pwd.
C [ title ]
Sets the title of any tables being printed as the result of a query or unset any such title. This command is equivalent to pset
title title. (The name of this command derives from ``caption'', as it was previously only used to set the caption in an HTML ta-
ble.)
connect (or c) [ dbname [ username ] [ host ] [ port ] ]
Establishes a new connection to a PostgreSQL server. If the new connection is successfully made, the previous connection is closed.
If any of dbname, username, host or port are omitted or specified as -, the value of that parameter from the previous connection is
used. If there is no previous connection, the libpq default for the parameter's value is used.
If the connection attempt failed (wrong user name, access denied, etc.), the previous connection will only be kept if psql is in
interactive mode. When executing a non-interactive script, processing will immediately stop with an error. This distinction was cho-
sen as a user convenience against typos on the one hand, and a safety mechanism that scripts are not accidentally acting on the
wrong database on the other hand.
copy { table [ ( column_list ) ] | ( query ) }
Performs a frontend (client) copy. This is an operation that runs an SQL COPY [copy(7)] command, but instead of the server reading
or writing the specified file, psql reads or writes the file and routes the data between the server and the local file system. This
means that file accessibility and privileges are those of the local user, not the server, and no SQL superuser privileges are
required.
The syntax of the command is similar to that of the SQL COPY [copy(7)] command. Note that, because of this, special parsing rules
apply to the copy command. In particular, the variable substitution rules and backslash escapes do not apply.
copy ... from stdin | to stdout reads/writes based on the command input and output respectively. All rows are read from the same
source that issued the command, continuing until . is read or the stream reaches EOF. Output is sent to the same place as command
output. To read/write from psql's standard input or output, use pstdin or pstdout. This option is useful for populating tables in-
line within a SQL script file.
Tip: This operation is not as efficient as the SQL COPY command because all data must pass through the client/server connection. For
large amounts of data the SQL command might be preferable.
copyright
Shows the copyright and distribution terms of PostgreSQL.
d[S+] [ pattern ]
For each relation (table, view, index, or sequence) matching the pattern, show all columns, their types, the tablespace (if not the
default) and any special attributes such as NOT NULL or defaults, if any. Associated indexes, constraints, rules, and triggers are
also shown, as is the view definition if the relation is a view. (``Matching the pattern'' is defined below.)
The command form d+ is identical, except that more information is displayed: any comments associated with the columns of the table
are shown, as is the presence of OIDs in the table.
By default, only user-created objects are shown; supply a pattern or the S modifier to include system objects.
Note: If d is used without a pattern argument, it is equivalent to dtvs which will show a list of all tables, views, and
sequences. This is purely a convenience measure.
da[S] [ pattern ]
Lists all available aggregate functions, together with their return type and the data types they operate on. If pattern is speci-
fied, only aggregates whose names match the pattern are shown. By default, only user-created objects are shown; supply a pattern or
the S modifier to include system objects.
db[+] [ pattern ]
Lists all available tablespaces. If pattern is specified, only tablespaces whose names match the pattern are shown. If + is
appended to the command name, each object is listed with its associated permissions.
dc[S] [ pattern ]
Lists all available conversions between character-set encodings. If pattern is specified, only conversions whose names match the
pattern are listed. By default, only user-created objects are shown; supply a pattern or the S modifier to include system objects.
dC [ pattern ]
Lists all available type casts. If pattern is specified, only casts whose source or target types match the pattern are listed.
dd[S] [ pattern ]
Shows the descriptions of objects matching the pattern, or of all visible objects if no argument is given. But in either case, only
objects that have a description are listed. By default, only user-created objects are shown; supply a pattern or the S modifier to
include system objects. ``Object'' covers aggregates, functions, operators, types, relations (tables, views, indexes, sequences),
large objects, rules, and triggers. For example:
=> dd version
Object descriptions
Schema | Name | Object | Description
------------+---------+----------+---------------------------
pg_catalog | version | function | PostgreSQL version string
(1 row)
Descriptions for objects can be created with the COMMENT [comment(7)] SQL command.
dD[S] [ pattern ]
Lists all available domains. If pattern is specified, only matching domains are shown. By default, only user-created objects are
shown; supply a pattern or the S modifier to include system objects.
des[+] [ pattern ]
Lists all foreign servers (mnemonic: ``external servers''). If pattern is specified, only those servers whose name matches the pat-
tern are listed. If the form des+ is used, a full desription of each server is shown, including the server's ACL, type, version,
and options.
deu[+] [ pattern ]
Lists all user mappings (mnemonic: ``external users''). If pattern is specified, only those mappings whose user names match the
pattern are listed. If the form deu+ is used, additional information about each mapping is shown.
Caution: deu+ might also display the user name and password of the remote user, so care should be taken not to disclose them.
dew[+] [ pattern ]
Lists all foreign-data wrappers (mnemonic: ``external wrappers''). If pattern is specified, only those foreign-data wrappers whose
name matches the pattern are listed. If the form dew+ is used, the ACL and options of the foreign-data wrapper are also shown.
df[antwS+] [ pattern ]
Lists available functions, together with their arguments, return types, and their function types: 'agg' (aggregate), 'normal',
'trigger', and 'window'. To display only functions of a specific type, use the corresponding letters a, n, t, or w. If pattern is
specified, only functions whose names match the pattern are shown. If the form df+ is used, additional information about each func-
tion, including volatility, language, source code and description, is shown. By default, only user-created objects are shown; supply
a pattern or the S modifier to include system objects.
Note: To look up functions taking arguments or returning values of a specific type, use your pager's search capability to scroll
through the df output.
dF[+] [ pattern ]
Lists available text search configurations. If pattern is specified, only configurations whose names match the pattern are shown.
If the form dF+ is used, a full description of each configuration is shown, including the underlying text search parser and the
dictionary list for each parser token type.
dFd[+] [ pattern ]
Lists available text search dictionaries. If pattern is specified, only dictionaries whose names match the pattern are shown. If
the form dFd+ is used, additional information is shown about each selected dictionary, including the underlying text search tem-
plate and the option values.
dFp[+] [ pattern ]
Lists available text search parsers. If pattern is specified, only parsers whose names match the pattern are shown. If the form
dFp+ is used, a full description of each parser is shown, including the underlying functions and the list of recognized token
types.
dFt[+] [ pattern ]
Lists available text search templates. If pattern is specified, only templates whose names match the pattern are shown. If the
form dFt+ is used, additional information is shown about each template, including the underlying function names.
dg[+] [ pattern ]
Lists all database roles. If pattern is specified, only those roles whose names match the pattern are listed. (This command is now
effectively the same as du). If the form dg+ is used, additional information is shown about each role, including the comment for
each role.
di[S+] [ pattern ]
ds[S+] [ pattern ]
dt[S+] [ pattern ]
dv[S+] [ pattern ]
In this group of commands, the letters i, s, t, and v stand for index, sequence, table, and view, respectively. You can specify any
or all of these letters, in any order, to obtain a listing of all the matching objects. For example, dit lists indexes and tables.
If + is appended to the command name, each object is listed with its physical size on disk and its associated description, if any.
By default, only user-created objects are shown; supply a pattern or the S modifier to include system objects.
If pattern is specified, only objects whose names match the pattern are listed.
dl This is an alias for lo_list, which shows a list of large objects.
dn[+] [ pattern ]
Lists available schemas (namespaces). If pattern (a regular expression) is specified, only schemas whose names match the pattern are
listed. Non-local temporary schemas are suppressed. If + is appended to the command name, each object is listed with its associated
permissions and description, if any.
do[S] [ pattern ]
Lists available operators with their operand and return types. If pattern is specified, only operators whose names match the pat-
tern are listed. By default, only user-created objects are shown; supply a pattern or the S modifier to include system objects.
dp [ pattern ]
Lists available tables, views and sequences with their associated access privileges. If pattern is specified, only tables, views
and sequences whose names match the pattern are listed.
The GRANT [grant(7)] and REVOKE [revoke(7)] commands are used to set access privileges.
dT[S+] [ pattern ]
Lists available data types. If pattern is specified, only types whose names match the pattern are listed. If + is appended to the
command name, each type is listed with its internal name and size, as well as its allowed values if it is an enum type. By default,
only user-created objects are shown; supply a pattern or the S modifier to include system objects.
du[+] [ pattern ]
Lists all database roles. If pattern is specified, only those roles whose names match the pattern are listed. If the form du+ is
used, additional information is shown about each role, including the comment for each role.
edit (or e) [ filename ]
If filename is specified, the file is edited; after the editor exits, its content is copied back to the query buffer. If no argument
is given, the current query buffer is copied to a temporary file which is then edited in the same fashion.
The new query buffer is then re-parsed according to the normal rules of psql, where the whole buffer is treated as a single line.
(Thus you cannot make scripts this way. Use i for that.) This means also that if the query ends with (or rather contains) a semi-
colon, it is immediately executed. In other cases it will merely wait in the query buffer.
Tip: psql searches the environment variables PSQL_EDITOR, EDITOR, and VISUAL (in that order) for an editor to use. If all of them
are unset, vi is used on Unix systems, notepad.exe on Windows systems.
ef [ function_description ]
This command fetches and edits the definition of the named function, in the form of a CREATE OR REPLACE FUNCTION command. Editing
is done in the same way as for e. After the editor exits, the updated command waits in the query buffer; type semicolon or g to
send it, or
to cancel.
The target function can be specified by name alone, or by name and arguments, for example foo(integer, text). The argument types
must be given if there is more than one function of the same name.
If no function is specified, a blank CREATE FUNCTION template is presented for editing.
echo text [ ... ]
Prints the arguments to the standard output, separated by one space and followed by a newline. This can be useful to intersperse
information in the output of scripts. For example:
=> echo `date`
Tue Oct 26 21:40:57 CEST 1999
If the first argument is an unquoted -n the trailing newline is not written.
Tip: If you use the o command to redirect your query output you might wish to use qecho instead of this command.
encoding [ encoding ]
Sets the client character set encoding. Without an argument, this command shows the current encoding.
f [ string ]
Sets the field separator for unaligned query output. The default is the vertical bar (|). See also pset for a generic way of set-
ting output options.
g [ { filename | |command } ]
Sends the current query input buffer to the server and optionally stores the query's output in filename or pipes the output into a
separate Unix shell executing command. A bare g is virtually equivalent to a semicolon. A g with argument is a ``one-shot'' alter-
native 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 ta-
ble.
H Turns on HTML query output format. If the HTML format is already on, it is switched back to the default aligned text format. This
command is for compatibility and convenience, but see pset about setting other output options.
i filename
Reads input from the file filename and executes it as though it had been typed on the keyboard.
Note: If you want to see the lines on the screen as they are read you must set the variable ECHO to all.
l (or list)
l+ (or list+)
List the names, owners, character set encodings, and access privileges of all the databases in the server. If + is appended to the
command name, database sizes, default tablespaces, and descriptions are also displayed. (Size information is only available for
databases that the current user can connect to.)
lo_export loid filename
Reads the large object with OID loid from the database and writes it to filename. Note that this is subtly different from the server
function lo_export, which acts with the permissions of the user that the database server runs as and on the server's file system.
Tip: Use lo_list to find out the large object's OID.
lo_import filename [ comment ]
Stores the file into a PostgreSQL large object. Optionally, it associates the given comment with the object. Example:
foo=> lo_import '/home/peter/pictures/photo.xcf' 'a picture of me'
lo_import 152801
The response indicates that the large object received object ID 152801, which can be used to access the newly-created large object
in the future. For the sake of readability, it is recommended to always associate a human-readable comment with every object. Both
OIDs and comments can be viewed with the lo_list command.
Note that this command is subtly different from the server-side lo_import because it acts as the local user on the local file sys-
tem, rather than the server's user and file system.
lo_list
Shows a list of all PostgreSQL large objects currently stored in the database, along with any comments provided for them.
lo_unlink loid
Deletes the large object with OID loid from the database.
Tip: Use lo_list to find out the large object's OID.
o [ {filename | |command} ]
Saves future query results to the file filename or pipes future results into a separate Unix shell to execute command. If no argu-
ments 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 vari-
ous backslash commands that query the database (such as d), but not error messages.
Tip: To intersperse text output in between query results, use qecho.
p Print the current query buffer to the standard output.
password [ username ]
Changes the password of the specified user (by default, the current user). This command prompts for the new password, encrypts it,
and sends it to the server as an ALTER ROLE command. This makes sure that the new password does not appear in cleartext in the com-
mand history, the server log, or elsewhere.
prompt [ text ] name
Prompts the user to set variable name. An optional prompt, text, can be specified. (For multi-word prompts, use single-quotes.)
By default, prompt uses the terminal for input and output. However, if the -f command line switch is used, prompt uses standard
input and standard output.
pset parameter [ value ]
This command sets options affecting the output of query result tables. parameter describes which option is to be set. The semantics
of value depend thereon.
Adjustable printing options are:
format Sets the output format to one of unaligned, aligned, wrapped, html, latex, or troff-ms. Unique abbreviations are allowed.
(That would mean one letter is enough.)
``Unaligned'' writes all columns of a row on a line, separated by the currently active field separator. This is intended to
create output that might be intended to be read in by other programs (tab-separated, comma-separated). ``Aligned'' mode is
the standard, human-readable, nicely formatted text output that is default.
``Wrapped'' is like aligned but wraps output to the specified width. If pset columns is zero (the default), wrapped mode
only affects screen output and wrapped width is controlled by the environment variable COLUMNS or the detected screen width.
If pset columns is set to a non-zero value, all output is wrapped, including file and pipe output.
The ``HTML'' and ``LaTeX'' modes put out tables that are intended to be included in documents using the respective mark-up
language. They are not complete documents! (This might not be so dramatic in HTML, but in LaTeX you must have a complete doc-
ument wrapper.)
columns
Controls the target width for the wrapped format, and width for determining if wide output requires the pager. Zero (the
default) causes the wrapped format to affect only screen output.
border The second argument must be a number. In general, the higher the number the more borders and lines the tables will have, but
this depends on the particular format. In HTML mode, this will translate directly into the border=... attribute, in the oth-
ers only values 0 (no border), 1 (internal dividing lines), and 2 (table frame) make sense.
expanded (or x)
You can specify an optional second argument, if it is provided it may be either on or off which will enable or disable
expanded mode. If the second argument is not provided then we will toggle between regular and expanded format. When expanded
format is enabled, query results are displayed in two columns, with the column name on the left and the data on the right.
This mode is useful if the data wouldn't fit on the screen in the normal ``horizontal'' mode.
Expanded mode is supported by all four output formats.
null The second argument is a string that should be printed whenever a column is null. The default is not to print anything, which
can easily be mistaken for, say, an empty string. Thus, one might choose to write pset null '(null)'.
fieldsep
Specifies the field separator to be used in unaligned output mode. That way one can create, for example, tab- or comma-sepa-
rated output, which other programs might prefer. To set a tab as field separator, type pset fieldsep ' '. The default field
separator is '|' (a vertical bar).
footer You can specify an optional second argument, if it is provided it may be either on or off which will enable or disable dis-
play of the default footer (x rows). If the second argument is not provided then we will toggle between on and off.
numericlocale
You can specify an optional second argument, if it is provided it may be either on or off which will enable or disable dis-
play of a locale-aware character to separate groups of digits to the left of the decimal marker. If the second argument is
not provided then we will toggle between on and off.
recordsep
Specifies the record (line) separator to use in unaligned output mode. The default is a newline character.
tuples_only (or t)
You can specify an optional second argument, if it is provided it may be either on or off which will enable or disable the
tuples only mode. If the second argument is not provided then we will toggle between tuples only and full display. Full dis-
play shows extra information such as column headers, titles, and various footers. In tuples only mode, only actual table data
is shown.
title [ text ]
Sets the table title for any subsequently printed tables. This can be used to give your output descriptive tags. If no argu-
ment is given, the title is unset.
tableattr (or T) [ text ]
Allows you to specify any attributes to be placed inside the HTML table tag. This could for example be cellpadding or
bgcolor. Note that you probably don't want to specify border here, as that is already taken care of by pset border.
pager Controls use of a pager for query and psql help output. If the environment variable PAGER is set, the output is piped to the
specified program. Otherwise a platform-dependent default (such as more) is used.
When the pager is off, the pager is not used. When the pager is on, the pager is used only when appropriate, i.e. the output
is to a terminal and will not fit on the screen. pset pager turns the pager on and off. Pager can also be set to always,
which causes the pager to be always used.
Illustrations on how these different formats look can be seen in the Examples [psql(1)] section.
Tip: There are various shortcut commands for pset. See a, C, H, , T, and x.
Note: It is an error to call pset without arguments. In the future this call might show the current status of all printing options.
q Quits the psql program.
qecho text [ ... ]
This command is identical to echo except that the output will be written to the query output channel, as set by o.
Resets (clears) the query buffer.
s [ filename ]
Print or save the command line history to filename. If filename is omitted, the history is written to the standard output. This
option is only available if psql is configured to use the GNU Readline library.
set [ name [ value [ ... ] ] ]
Sets the internal variable name to value or, if more than one value is given, to the concatenation of all of them. If no second
argument is given, the variable is just set with no value. To unset a variable, use the unset command.
Valid variable names can contain characters, digits, and underscores. See the section Variables [psql(1)] below for details. Vari-
able 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)].
Toggles the display of output column name headings and row count footer. This command is equivalent to pset tuples_only and is pro-
vided 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 [ on | off ]
Without parameter, toggles a display of how long each SQL statement takes, in milliseconds. With parameter, sets same.
w {filename | |command}
Outputs the current query buffer to the file filename or pipes it to the Unix command command.
x Toggles expanded table formatting mode. As such it is equivalent to pset expanded.
z [ pattern ]
Produces a list of all available tables, views and sequences with their associated access privileges. If a pattern is specified,
only tables,views and sequences whose names match the pattern are listed.
The GRANT [grant(7)] and REVOKE [revoke(7)] commands are used to set access privileges.
This is an alias for dp (``display privileges'').
! [ command ]
Escapes to a separate Unix shell or executes the Unix command command. The arguments are not further interpreted, the shell will see
them as is.
? Shows help information about the backslash commands.
PATTERNS
The various d commands accept a pattern parameter to specify the object name(s) to be displayed. In the simplest case, a pattern is just
the exact name of the object. The characters within a pattern are normally folded to lower case, just as in SQL names; for example, dt FOO
will display the table named foo. As in SQL names, placing double quotes around a pattern stops folding to lower case. Should you need to
include an actual double quote character in a pattern, write it as a pair of double quotes within a double-quote sequence; again this is in
accord with the rules for SQL quoted identifiers. For example, dt "FOO""BAR" will display the table named FOO"BAR (not foo"bar). Unlike
the normal rules for SQL names, you can put double quotes around just part of a pattern, for instance dt FOO"FOO"BAR will display the ta-
ble named fooFOObar.
Within a pattern, * matches any sequence of characters (including no characters) and ? matches any single character. (This notation is
comparable to Unix shell file name patterns.) For example, dt int* displays all tables whose names begin with int. But within double
quotes, * and ? lose these special meanings and are just matched literally.
A pattern that contains a dot (.) is interpreted as a schema name pattern followed by an object name pattern. For example, dt foo*.*bar*
displays all tables whose table name includes bar that are in schemas whose schema name starts with foo. When no dot appears, then the pat-
tern matches only objects that are visible in the current schema search path. Again, a dot within double quotes loses its special meaning
and is matched literally.
Advanced users can use regular-expression notations such as character classes, for example [0-9] to match any digit. All regular expression
special characters work as specified in in the documentation, except for . which is taken as a separator as mentioned above, * which is
translated to the regular-expression notation .*, ? which is translated to ., and $ which is matched literally. You can emulate these pat-
tern characters at need by writing ? for ., (R+|) for R*, or (R|) for R?. $ is not needed as a regular-expression character since the pat-
tern must match the whole name, unlike the usual interpretation of regular expressions (in other words, $ is automatically appended to your
pattern). Write * at the beginning and/or end if you don't wish the pattern to be anchored. Note that within double quotes, all regular
expression special characters lose their special meanings and are matched literally. Also, the regular expression special characters are
matched literally in operator name patterns (i.e., the argument of do).
Whenever the pattern parameter is omitted completely, the d commands display all objects that are visible in the current schema search
path -- this is equivalent to using the pattern *. To see all objects in the database, use the pattern *.*.
ADVANCED FEATURES
VARIABLES
psql provides variable substitution features similar to common Unix command shells. Variables are simply name/value pairs, where the value
can be any string of any length. To set variables, use the psql meta-command set:
testdb=> set foo bar
sets the variable foo to the value bar. To retrieve the content of the variable, precede the name with a colon and use it as the argument
of any slash command:
testdb=> echo :foo
bar
Note: The arguments of set are subject to the same substitution rules as with other commands. Thus you can construct interesting
references such as set :foo 'something' and get ``soft links'' or ``variable variables'' of Perl or PHP fame, respectively. Unfor-
tunately (or fortunately?), there is no way to do anything useful with these constructs. On the other hand, set bar :foo is a per-
fectly valid way to copy a variable.
If you call set without a second argument, the variable is set, with an empty string as value. To unset (or delete) a variable, use the
command unset.
psql's internal variable names can consist of letters, numbers, and underscores in any order and any number of them. A number of these
variables are treated specially by psql. They indicate certain option settings that can be changed at run time by altering the value of the
variable or represent some state of the application. Although you can use these variables for any other purpose, this is not recommended,
as the program behavior might grow really strange really quickly. By convention, all specially treated variables consist of all upper-case
letters (and possibly numbers and underscores). To ensure maximum compatibility in the future, avoid using such variable names for your own
purposes. A list of all specially treated variables follows.
AUTOCOMMIT
When on (the default), each SQL command is automatically committed upon successful completion. To postpone commit in this mode, you
must enter a BEGIN or START TRANSACTION SQL command. When off or unset, SQL commands are not committed until you explicitly issue
COMMIT or END. The autocommit-off mode works by issuing an implicit BEGIN for you, just before any command that is not already in a
transaction block and is not itself a BEGIN or other transaction-control command, nor a command that cannot be executed inside a
transaction block (such as VACUUM).
Note: In autocommit-off mode, you must explicitly abandon any failed transaction by entering ABORT or ROLLBACK. Also keep in mind
that if you exit the session without committing, your work will be lost.
Note: The autocommit-on mode is PostgreSQL's traditional behavior, but autocommit-off is closer to the SQL spec. If you prefer auto-
commit-off, you might wish to set it in the system-wide psqlrc file or your ~/.psqlrc file.
DBNAME The name of the database you are currently connected to. This is set every time you connect to a database (including program start-
up), but can be unset.
ECHO If set to all, all lines entered from the keyboard or from a script are written to the standard output before they are parsed or
executed. To select this behavior on program start-up, use the switch -a. If set to queries, psql merely prints all queries as they
are sent to the server. The switch for this is -e.
ECHO_HIDDEN
When this variable is set and a backslash command queries the database, the query is first shown. This way you can study the Post-
greSQL 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 exe-
cuted.
ENCODING
The current client character set encoding.
FETCH_COUNT
If this variable is set to an integer value > 0, the results of SELECT queries are fetched and displayed in groups of that many
rows, rather than the default behavior of collecting the entire result set before display. Therefore only a limited amount of memory
is used, regardless of the size of the result set. Settings of 100 to 1000 are commonly used when enabling this feature. Keep in
mind that when using this feature, a query might fail after having already displayed some rows.
Tip: Although you can use any output format with this feature, the default aligned format tends to look bad because each group of
FETCH_COUNT rows will be formatted separately, leading to varying column widths across the row groups. The other output formats work
better.
HISTCONTROL
If this variable is set to ignorespace, lines which begin with a space are not entered into the history list. If set to a value of
ignoredups, lines matching the previous history line are not entered. A value of ignoreboth combines the two options. If unset, or
if set to any other value than those above, all lines read in interactive mode are saved on the history list.
Note: This feature was shamelessly plagiarized from Bash.
HISTFILE
The file name that will be used to store the history list. The default value is ~/.psql_history. For example, putting:
set HISTFILE ~/.psql_history- :DBNAME
in ~/.psqlrc will cause psql to maintain a separate history for each database.
Note: This feature was shamelessly plagiarized from Bash.
HISTSIZE
The number of commands to store in the command history. The default value is 500.
Note: This feature was shamelessly plagiarized from Bash.
HOST The database server host you are currently connected to. This is set every time you connect to a database (including program start-
up), but can be unset.
IGNOREEOF
If unset, sending an EOF character (usually Control+D) to an interactive session of psql will terminate the application. If set to a
numeric value, that many EOF characters are ignored before the application terminates. If the variable is set but has no numeric
value, the default is 10.
Note: This feature was shamelessly plagiarized from Bash.
LASTOID
The value of the last affected OID, as returned from an INSERT or lo_insert command. This variable is only guaranteed to be valid
until after the result of the next SQL command has been displayed.
ON_ERROR_ROLLBACK
When on, if a statement in a transaction block generates an error, the error is ignored and the transaction continues. When interac-
tive, 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 con-
tinues. This has been the traditional behavior of psql but it is sometimes not desirable. If this variable is set, script processing
will immediately terminate. If the script was called from another script it will terminate in the same fashion. If the outermost
script was not called from an interactive psql session but rather using the -f option, psql will return error code 3, to distinguish
this case from fatal error conditions (error code 1).
PORT The database server port to which you are currently connected. This is set every time you connect to a database (including program
start-up), but can be unset.
PROMPT1
PROMPT2
PROMPT3
These specify what the prompts psql issues should look like. See Prompting [psql(1)] below.
QUIET This variable is equivalent to the command line option -q. It is probably not too useful in interactive mode.
SINGLELINE
This variable is equivalent to the command line option -S.
SINGLESTEP
This variable is equivalent to the command line option -s.
USER The database user you are currently connected as. This is set every time you connect to a database (including program start-up), but
can be unset.
VERBOSITY
This variable can be set to the values default, verbose, or terse to control the verbosity of error reports.
SQL INTERPOLATION
An additional useful feature of psql variables is that you can substitute (``interpolate'') them into regular SQL statements. The syntax
for this is again to prepend the variable name with a colon (:):
testdb=> set foo 'my_table'
testdb=> SELECT * FROM :foo;
would then query the table my_table. The value of the variable is copied literally, so it can even contain unbalanced quotes or backslash
commands. You must make sure that it makes sense where you put it. Variable interpolation will not be performed into quoted SQL entities.
One possible use of this mechanism is to copy the contents of a file into a table column. First load the file into a variable and then pro-
ceed as above:
testdb=> set content '''' `cat my_file.txt` ''''
testdb=> INSERT INTO my_table VALUES (:content);
One problem with this approach is that my_file.txt might contain single quotes. These need to be escaped so that they don't cause a syntax
error when the second line is processed. This could be done with the program sed:
testdb=> set content '''' `sed -e "s/'/''/g" < my_file.txt` ''''
If you are using non-standard-conforming strings then you'll also need to double backslashes. This is a bit tricky:
testdb=> set content '''' `sed -e "s/'/''/g" -e 's/\/\\/g' < my_file.txt` ''''
Note the use of different shell quoting conventions so that neither the single quote marks nor the backslashes are special to the shell.
Backslashes are still special to sed, however, so we need to double them. (Perhaps at one point you thought it was great that all Unix com-
mands use the same escape character.)
Since colons can legally appear in SQL commands, the following rule applies: the character sequence ``:name'' is not changed unless
``name'' is the name of a variable that is currently set. In any case you can escape a colon with a backslash to protect it from substitu-
tion. (The colon syntax for variables is standard SQL for embedded query languages, such as ECPG. The colon syntax for array slices and
type casts are PostgreSQL extensions, hence the conflict.)
PROMPTING
The prompts psql issues can be customized to your preference. The three variables PROMPT1, PROMPT2, and PROMPT3 contain strings and special
escape sequences that describe the appearance of the prompt. Prompt 1 is the normal prompt that is issued when psql requests a new command.
Prompt 2 is issued when more input is expected during command input because the command was not terminated with a semicolon or a quote was
not closed. Prompt 3 is issued when you run an SQL COPY command and you are expected to type in the row values on the terminal.
The value of the selected prompt variable is printed literally, except where a percent sign (%) is encountered. Depending on the next
character, certain other text is substituted instead. Defined substitutions are:
%M The full host name (with domain name) of the database server, or [local] if the connection is over a Unix domain socket, or
[local:/dir/name], if the Unix domain socket is not at the compiled in default location.
%m The host name of the database server, truncated at the first dot, or [local] if the connection is over a Unix domain socket.
%> The port number at which the database server is listening.
%n The database session user name. (The expansion of this value might change during a database session as the result of the command SET
SESSION AUTHORIZATION.)
%/ The name of the current database.
%~ Like %/, but the output is ~ (tilde) if the database is your default database.
%# If the session user is a database superuser, then a #, otherwise a >. (The expansion of this value might change during a database
session as the result of the command SET SESSION AUTHORIZATION.)
%R In prompt 1 normally =, but ^ if in single-line mode, and ! if the session is disconnected from the database (which can happen if
connect fails). In prompt 2 the sequence is replaced by -, *, a single quote, a double quote, or a dollar sign, depending on
whether psql expects more input because the command wasn't terminated yet, because you are inside a /* ... */ comment, or because
you are inside a quoted or dollar-escaped string. In prompt 3 the sequence doesn't produce anything.
%x Transaction status: an empty string when not in a transaction block, or * when in a transaction block, or ! when in a failed trans-
action block, or ? when the transaction state is indeterminate (for example, because there is no connection).
%digits
The character with the indicated octal code is substituted.
%:name:
The value of the psql variable name. See the section Variables [psql(1)] for details.
%`command`
The output of command, similar to ordinary ``back-tick'' substitution.
%[ ... %]
Prompts can contain terminal control characters which, for example, change the color, background, or style of the prompt text, or
change the title of the terminal window. In order for the line editing features of Readline to work properly, these non-printing
control characters must be designated as invisible by surrounding them with %[ and %]. Multiple pairs of these can occur within the
prompt. For example:
testdb=> set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%# '
results in a boldfaced (1;) yellow-on-black (33;40) prompt on VT100-compatible, color-capable terminals.
To insert a percent sign into your prompt, write %%. The default prompts are '%/%R%# ' for prompts 1 and 2, and '>> ' for prompt 3.
Note: This feature was shamelessly plagiarized from tcsh.
COMMAND-LINE EDITING
psql supports the Readline library for convenient line editing and retrieval. The command history is automatically saved when psql exits
and is reloaded when psql starts up. Tab-completion is also supported, although the completion logic makes no claim to be an SQL parser. If
for some reason you do not like the tab completion, you can turn it off by putting this in a file named .inputrc in your home directory:
$if psql
set disable-completion on
$endif
(This is not a psql but a Readline feature. Read its documentation for further details.)
ENVIRONMENT
COLUMNS
If pset columns is zero, controls the width for the wrapped format and width for determining if wide output requires the pager.
PAGER If the query results do not fit on the screen, they are piped through this command. Typical values are more or less. The default is
platform-dependent. The use of the pager can be disabled by using the pset command.
PGDATABASE
PGHOST
PGPORT
PGUSER Default connection parameters (see in the documentation).
PSQL_EDITOR
EDITOR
VISUAL Editor used by the e command. The variables are examined in the order listed; the first that is set is used.
SHELL Command executed by the ! command.
TMPDIR Directory for storing temporary files. The default is /tmp.
This utility, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see in the documentation).
FILES
o Before starting up, psql attempts to read and execute commands from the system-wide psqlrc file and the user's ~/.psqlrc file. (On Win-
dows, the user's startup file is named %APPDATA%postgresqlpsqlrc.conf.) See PREFIX/share/psqlrc.sample for information on setting up
the system-wide file. It could be used to set up the client or the server to taste (using the set and SET commands).
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-8.4.4. 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%postgresqlpsql_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. As of PostgreSQL 8.4 this is no longer allowed.
o psql is only guaranteed to work smoothly with servers of the same version. That does not mean other combinations will fail outright, but
subtle and not-so-subtle problems might come up. Backslash commands are particularly likely to fail if the server is of a newer version
than psql itself. However, backslash commands of the d family should work with servers of versions back to 7.4, though not necessarily
with servers newer than psql itself.
NOTES FOR WINDOWS USERS
psql is built as a ``console application''. Since the Windows console windows use a different encoding than the rest of the system, you
must take special care when using 8-bit characters within psql. If psql detects a problematic console code page, it will warn you at
startup. To change the console code page, two things are necessary:
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;
+-------+--------+
| 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 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
Application 2010-05-14 PSQL(1)