[singlepic id=9 w=320 h=240 float=left]
We visited Carizo state park in April for wild flowers.
Many hills and files were covered with yellow carpet of wild flowers. It’s amazing! With the low and dark clouds, it just looks like a beautiful oil painting.
Author Archives: yan
wget
wget -q –http-user=webmaster –http-passwd=PASSWORD “http://www.abcd.com” -O /var/tmp/logfile
Access https by telnet
openssl s_client -connect mysite.com:443
To retrieve a certificate
openssl s_client -connect sdms.ecp:443 2>&1 | sed -ne ‘/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p’
Useful page:
http://www.madboa.com/geek/openssl/
PHP session
Use both Session and cookie to keep security for the website
$_COOKIE[session_name()]
the session name is stored as cookie, other variables are stored as session var
auth.php
<?php
session_set_cookie_params(7200,’/’,”,true);
session_start();
if($_SESSION[‘auth’]!=’xxx’){
session_destroy();
header(“Location: ./login.php\n\n”);
exit;
}else{
//check fingerprint
$fp = $_SERVER[“HTTP_USER_AGENT”];
$fp .= $_SERVER[“REMOTE_ADDR”];
$fp = md5($fp);
if($_SESSION[‘par’] != $fp){
header(“Location: ./login.php\n\n”);
exit;
}
}
?>
login.php
check if ID, pass are matched with those in db….then
session_start();
$_SESSION[‘user_id’] = $uid;
$_SESSION[‘grp_id’] = $gid;
$_SESSION[‘auth’] = 1;
$fp = $_SERVER[“HTTP_USER_AGENT”];
$fp .= $_SERVER[“REMOTE_ADDR”];
$_SESSION[‘remote’] = md5($fp);
header(“Location: ./index.php”);
logout.php
session_set_cookie_params(7200,’/’,”,true);
session_start();
$_SESSION = array();
if(isset($_COOKIE[session_name()])){
$params = session_get_cookie_params();
setcookie(session_name(), ”, time()-3600,
$params[“path”], $params[“domain”],
$params[“secure”], $params[“httponly”]
);
}
session_destroy();
header(“Location: ./login.php\n\n”);
exit;
session_destroy() destroy the session, and cookie will be deleted as setting the cookie lifetime as a time past
SQL — MySQL
Insert
INSERT INTO tablename (col1, col2) VALUES(‘data1’, ‘data2’ );
Grant
GRANT ALL PRIVILEGES ON dbname.* to dbuser@localhost;
GRANT ALL PRIVILEGES ON dbname.* to dbuser@”%”;
GRANT SELECT ON dbname.dbtable to dbuser@”111.111.111.111″;
GRANT SELECT(colname) ON dbname.dbtable to dbuser@”111.111.111.111″;
set password for username = password(‘password’);
flush privileges;
Find
To avoid files started with “.” in find result
find . -name ‘.snapshot’ -prune -o -name ‘file.mp4’
To delete files older than 7*24h
find /var/tmp -mtime +7 -exec rm -f {} \;
mysqldump
1. dump all database into backup file
mysqldump –opt –all-databases > /tmp/databkup
(–opt includes lock table option)
2. dump several databases
mysqldump –opt –databases db1 db2 db3 > /tmp/databkup
3. dump single table
mysqldump –opt db1 table1 > /tmp/databkup
Touble shooting
Error: Access denied for user x@y to database z when using lock tables
mysqldump -u username -p database –single-transaction >dump.sql
User tar to back up db
mysql> FLUSH TABLES WITH READ LOCK;
(This will lock the db so it won’t be updated by other threads. Write threads by other process will wait till the lock is released)
#tar cvzf /var/tmp/datadump.tgz /var/lib/mysql/*
mysql> UNLOCK TABLES;
Restore data
lock tables bbb write;
mysql bbb < /data_backup/databkup
unlock tables;
MySQL interface — PHP
Connect and Close connection to DB
$DB_HOST = “localhost”;
$DB_NAME = “mysql”;
$DB_USER = “mysql”;
$DB_PASS = “password”;
function conn_db(){
global $DB_HOST;
global $DB_USER;
global $DB_PASS;
global $DB_NAME;
if(!($conn = mysql_connect($DB_HOST, $DB_USER, $DB_PASS))) {
echo “Failed to connect DB”;
echo mysql_error($conn);
die;
}
if(!(mysql_select_db($DB_NAME))) {
echo “Failed to select DB”;
echo mysql_error($conn);
die;
}
return $conn;
}
function close_db($conn){
mysql_close($conn);
}
$conn = conn_db();
$sql = “select * from users where date>’20081001′ order by id”;
if (!($rs=mysql_query($sql))) {
echo mysql_error($conn);
die;
}
while ($row = mysql_fetch_array($rs)) {
echo “$row[0] $row[1]\n”;
}
Reset db slave
Some old data were missingon db slave server
copy data from master db01.lalife.net to slave db02.lalife.net and reset slave
On Master:
Lock table
mysql> FLUSH TABLES WITH READ LOCK;
mysql> show master status;
+——————+———-+————–+——————+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+——————+———-+————–+——————+
| db01-bin.000901 | 84861692 | | |
+——————+———-+————–+——————+
cd /var/lib
tar cvfz TARFILE_NAME.tgz mysql/
mysql > unlock tables;
On Slave:
cd /var/tmp/
tar -zxvf db01_bk.tar.gz
service mysql stop
##backup old db
mv /www/mysql /www/mysql0603
mv /var/tmp/www/mysql/ /www/
service mysql start
mysql>STOP SLAVE;
mysql>RESET SLAVE;
mysql> CHANGE MASTER TO MASTER_HOST=’db001.lalife.net’, MASTER_USER=’replication’, MASTER_PASSWORD=’xxxxx’, MASTER_LOG_FILE=’db01-bin.000900′, MASTER_LOG_POS=13482116;
mysql>START SLAVE;
How to get master bin file and position:
On master server
mysql> show master status;
+——————+———–+————–+——————+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+——————+———–+————–+——————+
| db01-bin.000900 | 437292441 | | |
+——————+———–+————–+——————+
SSH key setup in cluster servers
Setup keys for xxx to login yyy without password
[xxx-sync@xxx ~]$ ssh-keygen -t dsa
cp id_dsa.pub to xxx /home/xxx-sync/.ssh