4.3.1. Using Options on the Command Line
Program options specified on the command line follow these
rules:
Options are given after the command name.
An option argument begins with one dash or two dashes,
depending on whether it has a short name or a long name.
Many options have both forms. For example,
-? and --help are the
short and long forms of the option that instructs a MySQL
program to display a help message.
Option names are case sensitive. -v and
-V are both legal and have different
meanings. (They are the corresponding short forms of the
--verbose and --version
options.)
Some options take a value following the option name. For
example, -h localhost or
--host=localhost indicate the MySQL server
host to a client program. The option value tells the program
the name of the host where the MySQL server is running.
-
For a long option that takes a value, separate the option
name and the value by an ‘=’
sign. For a short option that takes a value, the option
value can immediately follow the option letter, or there can
be a space between: -hlocalhost and
-h localhost are equivalent. An exception
to this rule is the option for specifying your MySQL
password. This option can be given in long form as
--password=pass_val
or as --password. In the latter case (with
no password value given), the program prompts you for the
password. The password option also may be given in short
form as
-ppass_val or as
-p. However, for the short form, if the
password value is given, it must follow the option letter
with no intervening space. The reason
for this is that if a space follows the option letter, the
program has no way to tell whether a following argument is
supposed to be the password value or some other kind of
argument. Consequently, the following two commands have two
completely different meanings:
shell> mysql -ptest
shell> mysql -p test
The first command instructs mysql to use
a password value of test, but specifies
no default database. The second instructs
mysql to prompt for the password value
and to use test as the default database.
Some options control behavior that can be turned on or off. For
example, the mysql client supports a
--column-names option that determines whether
or not to display a row of column names at the beginning of
query results. By default, this option is enabled. However, you
may want to disable it in some instances, such as when sending
the output of mysql into another program that
expects to see only data and not an initial header line.
To disable column names, you can specify the option using any of
these forms:
--disable-column-names
--skip-column-names
--column-names=0
The --disable and --skip
prefixes and the =0 suffix all have the same
effect: They turn the option off.
The “enabled” form of the option may be specified
in any of these ways:
--column-names
--enable-column-names
--column-names=1
If an option is prefixed by --loose, a program
does not exit with an error if it does not recognize the option,
but instead issues only a warning:
shell> mysql --loose-no-such-option
mysql: WARNING: unknown option '--no-such-option'
The --loose prefix can be useful when you run
programs from multiple installations of MySQL on the same
machine and list options in an option file, An option that may
not be recognized by all versions of a program can be given
using the --loose prefix (or
loose in an option file). Versions of the
program that recognize the option process it normally, and
versions that do not recognize it issue a warning and ignore it.
Another option that may occasionally be useful with
mysql is the --execute or
-e option, which can be used to pass SQL
statements to the server. The statements must be enclosed by
single or double quotation marks. If you wish to use quoted
values within a statement, you should use double quotes for the
statement, and single quotes for any quoted values within the
statement. When this option is used, mysql
executes the statements and exits.
For example, you can use the following command to obtain a list
of user accounts:
shell> mysql -u root -p --execute="SELECT User, Host FROM user" mysql
Enter password: ******
+------+-----------+
| User | Host |
+------+-----------+
| | gigan |
| root | gigan |
| | localhost |
| jon | localhost |
| root | localhost |
+------+-----------+
shell>
Note that the long form (--execute) must be
followed by an equals sign (=).
In the preceding example, the name of the
mysql database was passed as a separate
argument. However, the same statement could have been executed
using this command, which specifies no default database:
mysql> mysql -u root -p --execute="SELECT User, Host FROM mysql.user"
Multiple SQL statements may be passed on the command line,
separated by semicolons:
shell> mysql -u root -p -e "SELECT VERSION();SELECT NOW()"
Enter password: ******
+-----------------+
| VERSION() |
+-----------------+
| 5.1.5-alpha-log |
+-----------------+
+---------------------+
| NOW() |
+---------------------+
| 2006-01-05 21:19:04 |
+---------------------+
The --execute or -e option may
also be used to pass commands in an analogous fashion to the
ndb_mgm management client for MySQL Cluster.
See Section 16.3.6, “Safe Shutdown and Restart”, for an example.
