This is what I had to do to get some temperature reading from a Dell P850 in Ubuntu Linux.

Loading the IPMI kernel modules

root@server:~# modprobe ipmi_devintf
root@server:~# modprobe ipmi_si

Creating the device unless it’s already made
(I.e. if /dev/ipmi0 doesn’t already exist, do this step.)

root@server:~# mknod /dev/ipmi0 c 252 0

Installing the tools and reading temperatures

This will install the ipmitool package

root@server:~# apt-get install ipmitool

Read temperatures

root@server:~# ipmitool sdr type Temp
Temp | 01h | ok | 3.1 | 38 degrees C
Planar Temp | 04h | ok | 7.1 | 28 degrees C
Temp Interface | 53h | ns | 7.1 | Disabled

I wrote a munin plugin to parse and graph this too, shout if it’s interesting!

Tags: dell, ipmi, p850, poweredge, sensors, temperature

Everyone needs to store and get data from a database every now and then. MySQL can be an excellent choice for some.

Creating a table
This is how you create a simple table from the CLI, you can recognize the values if you use systems like phpmyadmin for modifying database structures.

mysql> CREATE TABLE mytable (
-> id INT NOT NULL AUTO_INCREMENT,
-> name VARCHAR(255) NOT NULL,
-> PRIMARY KEY(id)
-> );
Query OK, 0 rows affected (0.02 sec)

The MySQL reserved are upper cased, all the text in lower case are things
that you can change. This basically creates a table named ‘mytable’ with
two columns; “id” and “name”, id is an INT(eger) and name is a varchar of
max 255 characters.

AUTO_INCREMENT means that id will be automatically incremented if not defined.

Connecting to MySQL from PHP
Disclaimer: This is a very basic example, if you are coding for production use please at least look at the function mysql_real_escape_string() or a library
that will handle insertion and such.

The example above inserts a record in MySQL, the id will be automatically set to 1 (for the first row you insert, 2 for the next, etc.). To read this record out from the database again you can do something like this:

Warning:  mysql_connect() [function.mysql-connect]: Unknown MySQL server host 'mysqlhost' (1) in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 26

Warning:  mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 27
Data from MySQL
Warning:  mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 31

This piece of code will perform a “SELECT * FROM mytable” query (the * means every column from the table, you could get only the name by doing “SELECT name FROM mytable“.
Since there can be multiple rows we perform a while loop, so while $row gets fed with data from the mysql_fetch_assoc() function it will print the ‘id’ and ‘name’ columns from the table.

Select specific row(s) only (match on name)

Warning:  mysql_connect() [function.mysql-connect]: Unknown MySQL server host 'mysqlhost' (1) in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 43

Warning:  mysql_select_db(): supplied argument is not a valid MySQL-Link resource in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 44
Data from MySQL
Warning:  mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /home/espen/virtualhosts/www.cfg.no/htdocs/wp-content/plugins/exec-php/includes/runtime.php(42) : eval()'d code on line 48

Now we used the LIKE keyword in MySQL, the percent (%) sign is a wildcard.
This will get every row from the table where name begins with an E.

Homework: Now try to combine $_GET and $_POST + MySQL.

Tags: Learning PHP, mysql

I had promised myself that I would post every second day, but I didn’t know exactly where to go from what we have built up and I also became engaged, she said yes! So it has been crazy days.
But I’m happy, at least

I am going to continue with showing how to take use of some of the built-in string fuctions. These can be used to manipulate text variables that you might receive from the $_GET and $_POST variables.

Find occurrence of text in strings
You can for example use the function strstr() or stristr() if you want a cast-insensitive matching style.

Example

$mystring = 'this websites owner is nice';
if (strstr($mystring, 'website')) {
 echo 'I found the word "website" in the string.';
}

I can use double quotes in the string because I have it enclosed in single quotes.
If I were to use single quotes it would unquote the string and generate a syntax error.

If you replace strstr with stristr in the example, it would
also give a match if $mystring contains the word ‘Website’ with an upper case W.

explode() strings
If you get a string such as “one,two,three,four,five,six” and you would rather have
it indexed in an array you can use the function explode() to achieve this.

The build-in function explode() will parse a string and split it based on the
argument you give the function. An example will follow:

$mystring = "one,two,three,four;five,six,seven";
$myarray = explode(",", $mystring);

var_dump($myarray);

The first argument to explode is the delimiting character, while the other
is the string that will be split into an array. The result of this would be:

array(6) {
[0]=>
string(3) “one”
[1]=>
string(3) “two”
[2]=>
string(5) “three”
[3]=>
string(9) “four;five”
[4]=>
string(3) “six”
[5]=>
string(5) “seven”
}

Notice that $myarray[3] contains four;five, this is due to a common
mistake.. it can be hard to overlook, so can you figure out why it does that?

Anyways, you should check out the documentation and try out some
of the functions, because they are really easy to use and implement.

Good luck!

Tags: array, built-in, explode, functions, learn php, Learning PHP, php, stristr, strstr