Archive for the ‘SLES’ Category
July 21st, 2010 | 
Author: This is a list of handy MySQL commands that I use frequently.
Below when you see # it means from the unix shell. When you see mysql> it means from a MySQL prompt after logging into MySQL.
To login (from unix shell) use -h only if needed.
# [mysql dir]/bin/mysql -h hostname -u root -p
Create a database on the sql server.
mysql> create database [databasename];
List all databases on the sql server.
mysql> show databases;
Switch to a database.
mysql> use [db name];
To see all the tables in the db.
mysql> show tables;
To see database’s field formats.
mysql> describe [table name];
To delete a db.
mysql> drop database [database name];
To delete a table.
mysql> drop table [table name];
Show all data in a table.
mysql> SELECT * FROM [table name];
Returns the columns and column information pertaining to the designated table.
mysql> show columns from [table name];
Show certain selected rows with the value “whatever”.
mysql> SELECT * FROM [table name] WHERE [field name] = "whatever";
Show all records containing the name “Bob” AND the phone number ‘3444444′.
mysql> SELECT * FROM [table name] WHERE name = "Bob" AND phone_number = '3444444';
Show all records not containing the name “Bob” AND the phone number ‘3444444′ order by the phone_number field.
mysql> SELECT * FROM [table name] WHERE name != "Bob" AND phone_number = '3444444' order by phone_number;
Show all records starting with the letters ‘bob’ AND the phone number ‘3444444′.
mysql> SELECT * FROM [table name] WHERE name like "Bob%" AND phone_number = '3444444';
Show all records starting with the letters ‘bob’ AND the phone number ‘3444444′ limit to records 1 through 5.
mysql> SELECT * FROM [table name] WHERE name like "Bob%" AND phone_number = '3444444' limit 1,5;
Use a regular expression to find records. Use “REGEXP BINARY” to force case-sensitivity. This finds any record beginning with a.
mysql> SELECT * FROM [table name] WHERE rec RLIKE "^a";
Show unique records.
mysql> SELECT DISTINCT [column name] FROM [table name];
Show selected records sorted in an ascending (asc) or descending (desc).
mysql> SELECT [col1],[col2] FROM [table name] ORDER BY [col2] DESC;
Return number of rows.
mysql> SELECT COUNT(*) FROM [table name];
Sum column.
mysql> SELECT SUM(*) FROM [table name];
Join tables on common columns.
mysql> select lookup.illustrationid, lookup.personid,person.birthday from lookup left join person on lookup.personid=person.personid=statement to join birthday in person table with primary illustration id;
Creating a new user. Login as root. Switch to the MySQL db. Make the user. Update privs.
# mysql -u root -p
mysql> use mysql;
mysql> INSERT INTO user (Host,User,Password) VALUES('%','username',PASSWORD('password'));
mysql> flush privileges;
Change a users password from unix shell.
# [mysql dir]/bin/mysqladmin -u username -h hostname.blah.org -p password 'new-password'
Change a users password from MySQL prompt. Login as root. Set the password. Update privs.
# mysql -u root -p
mysql> SET PASSWORD FOR 'user'@'hostname' = PASSWORD('passwordhere');
mysql> flush privileges;
Recover a MySQL root password. Stop the MySQL server process.
Start again with no grant tables.
Login to MySQL as root.
Set new password.
Exit MySQL and restart MySQL server.
# /etc/init.d/mysql stop
# mysqld_safe --skip-grant-tables &
# mysql -u root
mysql> use mysql;
mysql> update user set password=PASSWORD("newrootpassword") where User='root';
mysql> flush privileges;
mysql> quit
# /etc/init.d/mysql stop
# /etc/init.d/mysql start
Set a root password if there is on root password.
# mysqladmin -u root password newpassword
Update a root password.
# mysqladmin -u root -p oldpassword newpassword
Allow the user “bob” to connect to the server from localhost using the password “passwd”. Login as root. Switch to the MySQL db. Give privs. Update privs.
# mysql -u root -p
mysql> use mysql;
mysql> grant usage on *.* to bob@localhost identified by 'passwd';
mysql> flush privileges;
Give user privilages for a db. Login as root. Switch to the MySQL db. Grant privs. Update privs.
# mysql -u root -p
mysql> use mysql;
mysql> INSERT INTO db (Host,Db,User,Select_priv,Insert_priv,Update_priv,Delete_priv,Create_priv,Drop_priv) VALUES ('%','databasename','username','Y','Y','Y','Y','Y','N');
mysql> flush privileges;
or
mysql> grant all privileges on databasename.* to username@localhost;
mysql> flush privileges;
To update info already in a table.
mysql> UPDATE [table name] SET Select_priv = 'Y',Insert_priv = 'Y',Update_priv = 'Y' where [field name] = 'user';
Delete a row(s) from a table.
mysql> DELETE from [table name] where [field name] = 'whatever';
Update database permissions/privilages.
mysql> flush privileges;
Delete a column.
mysql> alter table [table name] drop column [column name];
Add a new column to db.
mysql> alter table [table name] add column [new column name] varchar (20);
Change column name.
mysql> alter table [table name] change [old column name] [new column name] varchar (50);
Make a unique column so you get no dupes.
mysql> alter table [table name] add unique ([column name]);
Make a column bigger.
mysql> alter table [table name] modify [column name] VARCHAR(3);
Delete unique from table.
mysql> alter table [table name] drop index [colmn name];
Load a CSV file into a table.
mysql> LOAD DATA INFILE '/tmp/filename.csv' replace INTO TABLE [table name] FIELDS TERMINATED BY ',' LINES TERMINATED BY '\n' (field1,field2,field3);
Dump all databases for backup. Backup file is sql commands to recreate all db’s.
# [mysql dir]/bin/mysqldump -u root -ppassword --opt >/tmp/alldatabases.sql
Dump one database for backup.
# [mysql dir]/bin/mysqldump -u username -ppassword --databases databasename >/tmp/databasename.sql
Dump a table from a database.
# [mysql dir]/bin/mysqldump -c -u username -ppassword databasename tablename > /tmp/databasename.tablename.sql
Restore database (or database table) from backup.
# [mysql dir]/bin/mysql -u username -ppassword databasename < /tmp/databasename.sql
Create Table Example 1.
mysql> CREATE TABLE [table name] (firstname VARCHAR(20), middleinitial VARCHAR(3), lastname VARCHAR(35),suffix VARCHAR(3),officeid VARCHAR(10),userid VARCHAR(15),username VARCHAR(8),email VARCHAR(35),phone VARCHAR(25), groups VARCHAR(15),datestamp DATE,timestamp time,pgpemail VARCHAR(255));
Create Table Example 2.
mysql> create table [table name] (personid int(50) not null auto_increment primary key,firstname varchar(35),middlename varchar(50),lastnamevarchar(50) default 'bato');
Very often it happens that I must give support to a colleague or a customer on a Linux machine.
It’s very difficult to spell all bash command I will use to check which could be the problem, especially by phone.
When I discover “screen” it was a revelation.
With screen http://www.gnu.org/software/screen/screen.html you should share a linux session with other people.
You should use screen by simply ask to the user you want to assist to type on the console the following command :
screen
So if you can connect to the machine (even with ssh) you should run the following command :
screen -x
to share the same bash session.
Hope this help
Bye
Riccardo
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In this post I am going to talk about a very particular piece of hardware, unique on the market at this moment and that should be very useful for virtualization or clustering purpose, with a very low budget.
This product is called DamVirtualOne.
DamVirtualOne is a modular server (not a Blade) and have some very interesting feature :
- Fully redundant hot swap power supply.
- Fully redundant hot swap Gigabit ethernet switches with failover.
- Fully redundant hot swap storage controller, with multipathing and failover support.
- Up to six (6) compute module double socket (for Intel Xeon 5400 or 5500 CPU family).
- Up to 96GB of RAM each compute module.
- Up to 14 HDD SAS.
- Up to two redundant external SAS connection to storage expansion or SAS device connection (i.e. Tape Unit).
But the more important things that lead me to write this post is that storage is shared between the compute module, but not as other Blade Server on the market right now, with DamVirtualOne you should create a Virtual Disk (similar to a SAN LUN) and share it between all compute module if you need it.
At this time only IBM Blade Center S should have the same possibility, but it’s a Blade server, not a modular server, and there is a big price difference.
I had the luck to test the DamVirtualOne for few days (a lot) and I’ve installed the following :
- VMware ESXi 3.5
- VMware ESX 3.5
- Red Hat Enterprise Linux 5.3
- Microsoft Windows Server 2003
- Microsoft Windows Server 2008
I’ve created some fully function, and very performance VMware HA and DRS Cluster, and some Linux Cluster based on RHEL, and a large number of my previous post was written based on the installation above.
The standard server virtualization or clustering best practices require shared storage to use all benefits of the technology and this lead to buy SAN, Storage array (tipically Fibre Channel) who is very expensive, difficult to maintain and create a very complex infrastructure.
So you should know why I’m so excited about DamVirtualOne, because it’s a “single package” that contains all things you need for virtualization or clustering purpose : servers, storage and network a real datacenter all in one.
With the maximum configuration this machine should support up tp two hundred (200) Virtual Machine !! And his price will be very similar to two or three phisical server (as you are useful to see) and a shared storage, so you should understand that is a beautiful “piece of iron”.
I truly believe that modular server is sometimes under valuated, but in my opinion there is an enormous potential in it and it will be beautiful if this post lead some people to find out a solution, cheaper than other more famous one, using this piece of technology.
You should found more details about DamVirtualOne at the following websites.
Feel free to ask, they will answer you !
Riccardo
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This post assume you have just installed SLES on your server, and that the server in correctly configured to access internet.
This post also assume that you want to create a mail server for the following domain :
- yourdomain.com
- yourdomain.net
In this post we’re going to create a local mail server, that support the two domain above (but could be more than those) based on Postfix and Cyrus-Imap, with IMAP, IMAPS and SIEVE support, optionally you could add also Antivirus and AntiSpam using Amavisd-New with Clamav and SpamAssassin, and we also going to provide a webmail using squirrelmail.
This post assume you want to put this mail server on your DMZ with an ip address 192.168.100.1 and that you want to permit mail relay from your local network (192.168.1.0/24) and from authenticated user.
All the tasks above will be explained in the rest of the post.
This post will explain hot-to configure a unique IP Address on multiple NICs (Phisical or Virtual) on SuSE Linux Enterprise Server (9 or 10).
This post assume you have a 192.168.1.0/24 network and that you want to assign 192.168.1.1/24 to your system.
To enable Xvnc on Suse Linux you have to uncomment one of the services instances in /etc/xinetd.d/vnc.
Then you had to enable Xdmcp logins in the file:
/etc/opt/kde3/share/config/kdm/kdmrc
Start or restart XINETD on try to connect to your machine with a VNC Viewer or whatever you’ve configured in the services section (i.e. WebBrowser, Java Applet).
