Gentoo Blog

To compare the content of two fields in mysql and print the matching results do the following:

select * from user where username=password;

This would match all users that have the same username and password

This is our mysql table for proftpd with two users. One user has a clear text password ‘Clear_text’ and the other user has a Crypt password. The passwords are stored in the field passwd. Which we need to update for the user ftp.

mysql> select * from ftpuser;
+----+----------+-------------------------------------------+-----+------+---------------+---------------+-------+---------------------+---------------------+
| id | userid | passwd | uid | gid | homedir | shell | count | accessed | modified |
+----+----------+-------------------------------------------+-----+------+---------------+---------------+-------+---------------------+---------------------+
| 10 | ftp| *BD0359A2B6ZZHHA6A35B8D06DC1114D92CE3101 | 108 | 1002 | /storage/data | /sbin/nologin | 23 | 2011-01-19 13:07:33 | 2011-01-19 11:47:54 |
| 11 | upload | Clear_text | 108 | 1002 | /storage/data | /sbin/nologin | 529 | 2011-01-19 10:06:28 | 2011-01-06 16:01:30 |
+----+----------+-------------------------------------------+-----+------+---------------+---------------+-------+---------------------+---------------------+

We want to update the crypt password from the mysql shell. The following command will update the user ftp with a new crypt password:

update ftpuser set passwd=PASSWORD('KLatttGuya') where userid='ftp';

You can see the password in clear text here ‘KLatttGuya’ because of the option PASSWORD mysql knows that it must store a crypt password.

Recursively change all files in your current working directory including files in subdirectories to 644:

find . -type f -print0 | xargs -0 chmod 644

Recursively change all directories in your current working directory including subdirectories to 755:

find . -type d -print0 | xargs -0 chmod 755

when you see  a # it means use the command 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 user (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');

The Countdown begins

My new Dell Vostro 1500 was delivered this week. So i am busy installing Gentoo on it. I will get a howto up once i’m finished. With a Kernel .config and a few config files.

This is my first post on gentoo-blog.de. My new blog presenting you with interesting hacks and tricks around the great linux distro gentoo.