php - how to log errors to a log file in the current directory

$ vim debug.php


$ touch error_log.log
$ chmod a+rw error_log.log

[browse to the debug.php page and then cat the log file]

how to add/remove www. from domain name in .htaccess

to add/remove www. with mod rewrite :
cd public_html
vim .htaccess

# remove www
RewriteEngine On

RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ http://%1/$1 [R=301,L]


# insert www
RewriteEngine On

RewriteCond %{HTTP_HOST} !^www\.(.*)$ [NC]
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [R=301,L]

apache mod_proxy how to

Links :
-------
http://httpd.apache.org/docs/2.2/mod/mod_proxy.html#proxypassreverse
http://apache.webthing.com/mod_proxy_html/  -->   http://www.apachetutor.org/admin/reverseproxies

Modules :
---------
yum install httpd-devel
yum install libxml2-devel

Configuration:
--------------
cp proxy_html.conf /etc/httpd/conf/
vim /etc/httpd/conf/httpd.conf

LoadFile   /usr/lib/libxml2.so
LoadModule proxy_html_module modules/mod_proxy_html.so
Include conf/proxy_html.conf

(
Also Check :
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
)

Vhost :
-------
Example :

<VirtualHost 208.109.169.70:80>
    ServerAdmin "webmaster@upframr.com"
    ServerName upframr.com
    ServerAlias www.upframr.com
    MIMEMagicFile /dev/null
    CustomLog logs/upframr.com_access_log "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\""
    ErrorLog logs/upframr.com_error_log

    DocumentRoot "/home/admin2/public_html"
    <Directory "/home/admin2/public_html">
        Options +Indexes +FollowSymLinks
        Order allow,deny
        Allow from all
        AllowOverride All
        AddHandler mod_python .py
        PythonHandler mod_python.publisher
        PythonDebug On
    </Directory>

    Alias /mod_perl "/home/admin2/public_html/mod_perl"
    <Directory "/home/admin2/public_html/mod_perl">
        SetHandler perl-script
        PerlResponseHandler ModPerl::Registry
        PerlOptions +ParseHeaders
        Options +ExecCGI
    </Directory>

    <Location /perl-status>
        SetHandler perl-script
        PerlResponseHandler Apache::Status
        Order deny,allow
        Deny from all
        Allow from upframr.com
    </Location>

    ScriptAlias /cgi-bin "/home/admin2/public_html/cgi-bin"

    Alias /usage /var/www/stats/upframr.com
    <Directory /var/www/stats/upframr.com>
        Order allow,deny
        Allow from all
    </Directory>

    <Location /usage>
        Order allow,deny
        Allow from all
    </Location>
</VirtualHost>

Monitor Website in Real-Time with Apachetop

http://www.howtogeek.com/howto/ubuntu/monitor-your-website-in-real-time-with-apachetop/