Interactive command-line interface for HAWQ.
psql [<option> ...] [<dbname> [<username>]]
<general options> = [-c '<command>' | --command '<command>'] [-d <dbname> | --dbname <dbname>] [-f <filename> | --file <filename>] [-l | --list] [-v <assignment> | --set=<assignment> | --variable=<name><value>] [-X | --no-psqlrc] [-1 | --single-transaction] [-? | --help] [--version] <input and output options> = [-a | --echo-all] [-e | --echo-queries] [-E | --echo-hidden] [-L <filename> | --log-file <filename>] [-n | --noreadline] [-o <filename> | --output <filename>] [-q | --quiet] [-s | --single-step] [-S | --single-line] <output format options> = [-A | --no-align] [-F <separator> | --field-separator <separator>] [-H | --html] [-P <assignment> | --pset <assignment>] [-R <separator> | --record-separator <separator>] [-t | --tuples-only] [-T <table_options> | --table-attr [-V | --version] [-x | --expanded] <input and output options> = [-a | --echo-all] [-A | --no-align] [-c ’<command>’ | --command ’<command>’] [-d <dbname> | --dbname <dbname>] [-e | --echo-queries] [-E | --echo-hidden] [-f <filename> | --file <filename>] [-F <separator> | --field-separator <separator>] [-H | --html] [-l | --list] [-L <filename> | --log-file <filename>] [-o <filename> | --output <filename>] [-P <assignment> | --pset <assignment>] [-q | --quiet] [-R <separator> | --record-separator <separator>] [-s | --single-step] [-S | --single-line] [-t | --tuples-only] [-T <table_options> | --table-attr [-V | --version] [-x | --expanded] <connection_options> = [-h <host> | --host <host>] [-p <port> | -- port <port>] [-U <username> | --username <username>] [-W | --password]
psql is a terminal-based front-end to HAWQ. It enables you to type in queries interactively, issue them to HAWQ, 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.
Note: HAWQ queries timeout after a period of 600 seconds. For this reason, long-running queries may appear to hang in
plsql until results are processed or until the timeout period expires.
psqlis to execute the specified command string, and then exit. This is useful in shell scripts. <command> must be either a command string that is completely parseable by the server, or a single backslash command. Thus you cannot mix SQL and
psqlmeta-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.
If this parameter contains an equals sign, it is treated as a
conninfo string; for example you can pass
'dbname=postgres user=username password=mypass' as
psqlterminates. 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
-fenables some nice features such as error messages with line numbers.
\setinternal command. <NAME> will be set to <VALUE>. 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 could be overwritten later.
psqlrcfile nor the user’s
psqlexecutes a script with the
-foption, adding this option wraps
BEGIN/COMMITaround 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
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.
psqlcommand line arguments, then exit.
Input and Output Options
\dand other backslash commands. You can use this to study
psql’s internal operations.
psqlshould 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
Output Format Options
\pseton 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
\pset tuples_onlyand is provided for convenience.
PGHOSTor defaults to localhost.
PGPORTor defaults to 5432.
PGUSERor defaults to the current system role name.
psqlshould automatically prompt for a password whenever the server requests password authentication. However, currently password request detection is not totally reliable, hence this option to force a prompt. If no password prompt is issued and the server requires password authentication, the connection attempt will fail.
~/.pgpassfile, 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: This option remains set for the entire session, and so it affects uses of the meta-command
\connect as well as the initial connection attempt.
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.
Connecting to a Database
psql is a client application for HAWQ. To connect to a database you must know the name of your target database, the host name and port number of the HAWQ master server and what database user name you want to connect as. Use the
-U command line options, respectively, to specify these parameters to
psql. 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 master server on the local host, or via TCP/IP to
localhost on machines that do not have UNIX-domain sockets. The default master port number is 5432. If you use a different port for the master, you must specify the port. The default database 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 are not right, you can save yourself some typing by setting any or all of the environment variables
PGUSER to appropriate values.
It is also convenient to have a
~/.pgpass file to avoid regularly having to type in passwords. This file should reside in your home directory and contain lines of the following format:
The permissions on
.pgpass must disallow any access to world or group (for example:
chmod 0600 ~/.pgpass). If the permissions are less strict than this, the file will be ignored. (The file permissions are not currently checked on Microsoft Windows clients, however.)
If the connection could not be made for any reason (insufficient privileges, server is not running, 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 a regular user or
=# for a superuser. For example:
At the prompt, the user may 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.
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 may quote it with a single quote. To include a single quote into such an argument, use two single quotes. Anything contained in single quotes is furthermore subject to C-like substitutions for
\n (new line),
\digits (octal), and
If an unquoted argument begins with a colon (
:), it is taken as a
psql variable and the value of the variable is used as the argument instead.
Arguments that are enclosed in backquotes (
`) are taken as a command line that is passed to the shell. The output of the command (with any trailing newline removed) is taken as the argument value. The above escape sequences also apply in backquotes.
Some commands take an SQL identifier (such as a table name) as argument. These arguments follow the syntax rules of SQL: Unquoted letters are forced to lowercase, while double quotes (
") protect letters from case conversion and allow incorporation of whitespace into the identifier. Within double quotes, paired double quotes reduce to a single double quote in the resulting name. For example,
FOO"BAR"BAZ is interpreted as
"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:
\psetfor a more general solution.
psqlis in interactive mode. When executing a non-interactive script, processing will immediately stop with an error. This distinction was chosen as a user convenience against typos, and a safety mechanism that scripts are not accidentally acting on the wrong database.
TCP/IP, etc.), the host, and the port.
COPYcommand, but instead of the server reading or writing the specified file,
psqlreads 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 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
pstdout. This option is useful for populating tables in-line within a SQL script file.
This operation is not as efficient as the SQL
COPY command because all data must pass through the client/server connection.
NOT NULLor defaults, if any. Associated indexes, constraints, rules, and triggers are also shown, as is the view definition if the relation is a view.
- The command form
\d+is identical, except that more information is displayed: any comments associated with the columns of the table are shown, as is the presence of OIDs in the table.
The command form
\dSis identical, except that system information is displayed as well as user information.For example,
\dtdisplays user tables, but not system tables;
\dtSdisplays both user and system tables.Both these commands can take the
+parameter to display additional information, as in
\dis used without a pattern argument, it is equivalent to
\dtvswhich will show a list of all tables, views, and sequences.
\df+is used, additional information about each function, including language and description, is shown. To reduce clutter,
\dfdoes not show data type I/O functions. This is implemented by ignoring functions that accept or return type
Sstand for index, sequence, table, parent table, view, external table, 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
Srestricts 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 a pattern is specified, only objects whose names match the pattern are listed.
\lo_list, which shows a list of large objects.
+is appended to the command name, each object is listed with its associated permissions and description, if any.
REVOKEcommands are used to set access privileges.
\dT+shows extra information.
psql, where the whole buffer is treated as a single line. (Thus you cannot make scripts this way. Use
\ifor 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.
psql searches the environment variables
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.
If you use the
\o command to redirect your query output you may wish to use
'echo instead of this command.
|). See also
\psetfor a generic way of setting output options.
\gis virtually equivalent to a semicolon. A
\gwith argument is a one-shot alternative to the
psqlwill list all the commands for which syntax help is available. Use an asterisk (*) to show syntax help on all SQL commands. To simplify typing, commands that consists of several words do not have to be quoted.
\psetabout setting other output options.
+is appended to the command name, database descriptions are also displayed.
lo_export, which acts with the permissions of the user that the database server runs as and on the server’s file system. Use
\lo_listto find out the large object’s OID.
mydb=> \lo_import '/home/gpadmin/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 remember if one wants to access the object ever again. For that reason, you should always associate a human-readable comment with every object. Those can then be seen with the
\lo_list command. Note that this command is subtly different from the server-side
lo_import because it acts as the local user on the local file system, rather than the server’s user and file system.
\lo_listto find out the large object’s OID.
\d), but not error messages. To intersperse text output in between query results, use
ALTER ROLEcommand. This makes sure that the new password does not appear in cleartext in the command history, the server log, or elsewhere.
\prompt uses the terminal for input and output. However, you can use the
-f command line switch to specify standard input and standard output.
format– Sets the output format to one of u
roff-ms, or w
rapped. First letter abbreviations are allowed. 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. 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 documents! (This might not be so dramatic in HTML, but in LaTeX you must have a complete document wrapper.)
The wrapped option sets the output format like the
alignedparameter, but wraps wide data values across lines to make the output fit in the target column width. The target width is set with the
columnsoption. To specify the column width and select the wrapped format, use two \pset commands; for example, to set the with to 72 columns and specify wrapped format, use the commands
\pset columns 72and then
\pset format wrapped.
psqldoes not attempt to wrap column header titles, the wrapped format behaves the same as aligned if the total width needed for column headers exceeds the target.
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 others only values
1(internal dividing lines), and
2(table frame) make sense.
columns– Sets the target width for the
wrappedformat, and also the width limit for determining whether output is wide enough to require the pager. The default is zero. Zero causes the target width to be controlled by the environment variable
COLUMNS, or the detected screen width if
COLUMNSis not set. In addition, if
COLUMNSis zero, then the wrapped format affects screen output only. If
COLUMNSis nonzero, then file and pipe output is wrapped to that width as well.
After setting the target width, use the command
\pset format wrappedto enable the wrapped format.
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 would not fit on the screen in the normal horizontal mode. Expanded mode is supported by all four output formats.
old-ascii] – Sets the border line drawing style to one of unicode, ascii, or old-ascii. Unique abbreviations, including one letter, are allowed for the three styles. The default setting is
ascii. This option only affects the
ascii– uses plain ASCII characters. Newlines in data are shown using a + symbol in the right-hand margin. When the wrapped format wraps data from one line to the next without a newline character, a dot (.) is shown in the right-hand margin of the first line, and again in the left-hand margin of the following line.
old-ascii– style uses plain ASCII characters, using the formatting style used in PostgreSQL 8.4 and earlier. Newlines in data are shown using a : symbol in place of the left-hand column separator. When the data is wrapped from one line to the next without a newline character, a ; symbol is used in place of the left-hand column separator.
unicode– style uses Unicode box-drawing characters. Newlines in data are shown using a carriage return symbol in the right-hand margin. When the data is wrapped from one line to the next without a newline character, an ellipsis symbol is shown in the right-hand margin of the first line, and again in the left-hand margin of the following line.
bordersetting is greater than zero, this option also determines the characters with which the border lines are drawn. Plain ASCII characters work everywhere, but Unicode characters look nicer on displays that recognize them.
null 'string'– The second argument is a string to print whenever a column is null. The default is not to print anything, which can easily be mistaken for an empty string. For example, the command
null '(empty)'displays (empty) in null columns.
fieldsep– Specifies the field separator to be used in unaligned output mode. That way one can create, for example, tab- or comma-separated output, which other programs might prefer. To set a tab as field separator, type
\pset fieldsep '\t'. The default field separator is
'|'(a vertical bar).
footer– Toggles the display of the default footer (x rows).
numericlocale– Toggles the display of a locale-aware character to separate groups of digits to the left of the decimal marker. It also enables a locale-aware decimal marker.
recordsep– Specifies the record (line) separator to use in unaligned output mode. The default is a newline character.
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.
T[<text>] – Allows you to specify any attributes to be placed inside the HTML table tag. This could for example be
bgcolor. Note that you probably don’t want to specify border here, as that is already taken care of by
t[ novalue | on | off ] – The
\pset tuples_onlycommand by itself toggles between tuples only and full display. The values
offset the tuples display, regardless of the current setting. Full display may show extra information such as column headers, titles, and various footers. In tuples only mode, only actual table data is shown The
\tcommand is equivalent to
tuples_onlyand is provided for convenience.
pager– Controls the use of a pager for query and
psqlhelp output. When
on, if the environment variable
PAGERis set, the output is piped to the specified program. Otherwise a platform-dependent default (such as
more) is used. When
off, the pager is not used. When
on, the pager is used only when appropriate. Pager can also be set to
always, which causes the pager to be always used.
\echoexcept that the output will be written to the query output channel, as set by
Valid variable names can contain characters, digits, and underscores. See “Variables” in Advanced Features. 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 topic about variables.
This command is totally separate from the SQL command
\tcommand by itself toggles a display of output column name headings and row count footer. The values
offset the tuples display, regardless of the current setting.This command is equivalent to
\pset tuples_onlyand is provided for convenience.
\timingcommand by itself toggles a display of how long each SQL statement takes, in milliseconds. The values
offset the time display, regardless of the current setting.
\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). Unlike the normal rules for SQL names, you can put double quotes around just part of a pattern, for instance
\dt FOO"FOO"BAR will display the table named
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,
? 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 starts with
bar that are in schemas whose schema name starts with
foo. When no dot appears, then the pattern matches only objects that are visible in the current schema search path. Again, a dot within double quotes loses its special meaning and is matched literally.
Advanced users can use regular-expression notations. All regular expression special characters work as specified in the PostgreSQL documentation on regular expressions, except for
. which is taken as a separator as mentioned above,
* which is translated to the regular-expression notation
? which is translated to
.. You can emulate these pattern characters at need by writing
R?. Remember that the pattern must match the whole name, unlike the usual interpretation of regular expressions; 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 (such as the argument of
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
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
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. Unfortunately, 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
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 might behave unexpectedly. 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 are as follows:
START TRANSACTIONSQL command. When off or unset, SQL commands are not committed until you explicitly issue
END. The autocommit-on mode works by issuing an implicit
BEGINfor you, just before any command that is not already in a transaction block and is not itself a
BEGINor other transaction-control command, nor a command that cannot be executed inside a transaction block (such as
In autocommit-off mode, you must explicitly abandon any failed transaction by entering
ROLLBACK. Also keep in mind that if you exit the session without committing, your work will be lost.
The autocommit-on mode is PostgreSQL’s traditional behavior, but autocommit-off is closer to the SQL spec. If you prefer autocommit-off, you may wish to set it in your
-a. If set to queries,
psqlmerely prints all queries as they are sent to the server. The switch for this is
-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.
SELECTqueries 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 may fail after having already displayed some rows.
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.
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
ignorebothcombines 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.
~/.psql_history. For example, putting
\set HISTFILE ~/.psql_history- :DBNAME
~/.psqlrc will cause
psql to maintain a separate history for each database.
CTRL+D) to an interactive session of
psqlwill terminate the application. If set to a numeric value, that many
EOFcharacters are ignored before the application terminates. If the variable is set but has no numeric value, the default is
lo_insertcommand. This variable is only guaranteed to be valid until after the result of the next SQL command has been displayed.
SAVEPOINTfor you, just before each command that is in a transaction block, and rolls back to the savepoint on error.
psqlbut 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
psqlsession but rather using the
psqlwill return error code 3, to distinguish this case from fatal error conditions (error code 1).
psqlissues should look like. See “Prompting,” below.
-q. It is not very useful in interactive mode.
terseto control the verbosity of error reports.
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.
A popular application of this facility is to refer to the last inserted OID in subsequent statements to build a foreign key scenario. Another possible use of this mechanism is to copy the contents of a file into a table column. First load the file into a variable and then proceed as above.
testdb=> \set content '''' `cat my_file.txt` '''' testdb=> INSERT INTO my_table VALUES (:content);
One problem with this approach is that
my_file.txt might contain single quotes. These need to be escaped so that they don’t cause a syntax error when the second line is processed. This could be done with the program
testdb=> \set content '''' `sed -e "s/'/''/g" < my_file.txt` ''''
If you are using non-standard-conforming strings, then you’ll also need to use 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.
Since colons may 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 substitution. (The colon syntax for variables is standard SQL for embedded query languages, such as ECPG. The colon syntax for array slices and type casts are HAWQ extensions, hence the conflict.)
psql issues can be customized to your preference. The three variables
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:
[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.
[local]if the connection is over a UNIX domain socket.
SET SESSION AUTHORIZATION.)
%/, but the output is
~(tilde) if the database is your default database.
#, otherwise a
>. (The expansion of this value might change during a database session as the result of the command
SET SESSION AUTHORIZATION.)
=, but is
^if in single-line mode, and
!if the session is disconnected from the database (which can happen if
\connectfails). In prompt 2, the sequence is replaced by
*, a single quote (
'), a double quote (
"), or a dollar sign (
$), depending on whether
psqlexpects more input because: the command is not yet terminated, you are inside a
/* ... */comment, or you are inside a quoted or dollar-escaped string. In prompt 3, no substitution is produced.
*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).
psqlvariable name. See “Variables” in Advanced Features for details.
%]. Multiple pairs of these may occur within the prompt. For example,
testdb=> \set PROMPT1 '%[%033[1;33;40m%]%n@%/%R%[%033[0m%]%#'
results in a boldfaced (
1;) yellow-on-black (
33;40) prompt on VT100-compatible, color-capable terminals. To insert a percent sign into your prompt, write
%%. The default prompts are
'%/%R%# ' for prompts 1 and 2, and
'>> ' for prompt 3.
psql supports the NetBSD libedit 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
less. The default is platform-dependent. The use of the pager can be disabled by using the
\ecommand. The variables are examined in the order listed; the first that is set is used.
Before starting up,
psql attempts to read and execute commands from the user’s
The command-line history is stored in the file
psql only works smoothly with servers of the same version. That does not mean other combinations will fail outright, but subtle and not-so-subtle problems might come up. Backslash commands are particularly likely to fail if the server is of a different version.
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 detects a problematic console code page, it will warn you at startup. To change the console code page, two things are necessary:
Set the code page by entering:
cmd.exe /c chcp 1252
1252 is a character encoding of the Latin alphabet, used by Microsoft Windows for English and some other Western languages. If you are using Cygwin, you can put this command in
Set the console font to Lucida Console, because the raster font does not work with the ANSI code page.
psql in interactive mode:
$ psql -p 54321 -U sally mydatabase
psql interactive mode, 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
Look at the table definition:
testdb=> \d my_table Table "my_table" Attribute | Type | Modifier -----------+---------+-------------------- first | integer | not null default 0 second | text |
psql in non-interactive mode by passing in a file containing SQL commands:
$ psql -f /home/gpadmin/test/myscript.sql