Linux Common

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whois from registrar end

http://reports.internic.net/cgi/whois


File system hierarchy

http://en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard




What is a port?

Short answer: A communication channel for computers in networks. 





Set time for history command in linux

If you are using a bash shell then using following command you can set the time in history
HISTTIMEFORMAT="%D %T "






Kernel Compilation Full Note


http://www.digitalhermit.com/linux/Kernel-Build-HOWTO.html




Booting Process

http://www.yolinux.com/TUTORIALS/LinuxTutorialInitProcess.html




Litespeed

http://www.litespeedtech.com/docs/webserver/install/
http://www.litespeedtech.com/products/webserver/download/
http://www.litespeedtech.com/docs/webserver/admin/
http://www.litespeedtech.com/support/forum/
http://www.litespeedtech.com/support/wiki/doku.php?id=litespeed_wiki:license:all_about_licenses
http://litespeedtech.com/support/forum/showthread.php?t=2160





How to configure named on a machine


http://nixcraft.com/getting-started-tutorials/525-ubuntu-linux-setup-configure-domain-name-server-bind.html




Setting Up an NFS Server

http://www.tldp.org/HOWTO/NFS-HOWTO/server.html#SERVERINTRO





FSCK

fsck -pcfv /dev/sdb1




Trace Email Address Source


This tool attempts to locate the source IP address of an email based on the email headers (Where did the email come  
from)
http://whatismyipaddress.com/staticpages/index.php/trace-email-source-IP-address


cPanel theme paths:

/usr/local/cpanel/base/frontend

WHM theme paths:

/usr/local/cpanel/whostmgr/docroot/themes





Disabling mod_security using .htaccess

This should only be used as a last resort, but if you cannot run your site and your host won't adjust their mod_security configuration accordingly you can normally disable mod_security for your site by adding the following to your site's .htaccess file

SecFilterEngine Off





Difference between pop and imap


http://email.cityu.edu.hk/faq/popimap.htm

http://saturn.med.nyu.edu/it/help/email/imap/index.html

http://www.helpdesk.ilstu.edu/kb/index.phtml?kbid=1172




To find the installed perl modules

http://www.cyberciti.biz/faq/how-do-i-find-out-what-perl-modules-already-installed-on-my-system/

To display the list enter the following command:

$ instmodsh

Output:

Available commands are:
l            - List all installed modules
m    - Select a module
q            - Quit the program
cmd?

At cmd? prompt type l to list all installed modules:

cmd? l




Re initialize CPAN

Apparently you start cpan with:

perl -MCPAN -e shell

When you get to the prompt, you enter:

o conf init

and accept all the default values (and pick a few mirrors) rather than playing with stuff you don't understand.





Directory contents listing

This can be done with creating a file called .htaccess with the following contents inside it
=========================
Options +Indexes
=========================
"403: Directory index forbidden by rule" CAUSE "Directory index forbidden" error occurs if there is  
no index file in the directory and directory indexing is disabled in Apache configuration. See  
http://httpd.apache.org/docs/2.0/mod/mod_dir.html#directoryindex and 
http://httpd.apache.org/docs/2.0/mod/core.html#options for more information. RESOLUTION
To avoid this error the index file should be put into the directory. Index file's extensions are  
defined in httpd.conf by means of DirectoryIndex directive, for example:
   DirectoryIndex at_domains_index.html index.html index.html.var index.shtml index.php index.htm

see http://httpd.apache.org/docs/2.0/mod/mod_dir.html#directoryindex for the detailed description.

Or enable directory indexing with "Options +Indexes" directive for the domain by means of vhost.conf or for the whole server in httpd.conf, see http://httpd.apache.org/docs/2.0/mod/core.html#options for the directive syntax.

Restart Apache if you changed any configuration file.






setuid:

Normally, if a person executes an executable (assuming he has the privileges to do so), it will  
execute under that person's privileges, so the program will only be able to read and write to stuff 
that the running user can do. When an executable has the setuid bit set, the executable will execute 
under that priviledges of the owner of the executable, regardless of the user executing it.
For example, the "/usr/bin/passwd" executable is owned by root, is executable by everyone, and has 
the setuid bit set, such that anybody can call it to change their own password, but it runs with the 
privileges needed to modify the /etc/passwd and /etc/shadow files, which only root has.


When a binary executable file has been given the setuid attribute, normal users on the system can execute this file 
and gain the privileges of the user who owns the file (commonly root) within the created process. 


setgid:

Normally, if a person creates a file, it is owned by that user's user and group. If a person creates 
a file in a directory that has the setgid bit set, the group of new file will be instead set to be 
the same as the group of the directory by default.
For example, you have a directory that you plan to use to store web pages. You might want to set the 
setgid bit on it and change its group to "www". That way, whenever someone puts a new page in the 
directory, it will inherit the "www" group, regardless of the group of their creator. Suppose then 
the files are given "664" permission; then all the web administrators in the "www" group will be 
able to modify the files. 

sticky:

Normally, if someone has write permission to a directory, they can delete and move files inside the  
directory. With the sticky bit set on the directory, only the creator of the file or directory   
inside can delete or move it.
For example, the /tmp directory is readable & writable & executable by everyone, so that everyone 
can access and create temp files inside it. But it has the sticky bit set, so that I can't mess with  
someone else's temp files.
The most common use of the sticky bit today is on directories, where, when set, items inside the 
directory can be renamed or deleted only by the item's owner, the directory's owner, or the 
superuser (Without the sticky bit set, a user with write and execute permissions for the directory 
can rename or delete any file inside, regardless of the file's owner.) Frequently this is set on the 
/tmp directory to prevent ordinary users from deleting or moving other users' files.
To set the sticky bit in a directory, do the following:
chmod +t data 






Group Sharing a Directory (sgid , getfacl and setfacl )


 http://www.udel.edu/topics/os/unix/general/groupsharing.html
 https://help.webfaction.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=130





redirect to another url - no change in address bar

<html>
<head>
<title>Your Title</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<script language="JavaScript">
document.write("<frameset rows=* frameborder=NO border=0 framespacing=0 cols=*>");
document.write("<frame name=main src=http://mycutelife.net/"+document.location.search+">");
document.write("</frameset>");
document.write("<noframes>");
document.write("<body bgcolor=#FFFFF0 text=#000000>");
document.write("</body></noframes>");
</script>
</html>




Bypass Authentication Or Access Requirements

http://wiki.apache.org/httpd/BypassAuthenticationOrAuthorizationRequirements
<Directory /home/www/site1/private>
 AuthUserFile /home/www/site1-passwd
 AuthType Basic
 AuthName MySite
 Require valid-user
 Order allow,deny
 Allow from 172.17.10
 Satisfy any
</Directory>
This will force everyone from the outside to authenticate, but those coming from the LAN IP range would not be 
required to do so. Apache will let them access the directory without authenticating. You can add other hostnames  
(local or remote) to the Allow directive to give them access to the directory as well.





redirect all http to https

RewriteEngine on
Options +FollowSymLinks
RewriteCond %{SERVER_PORT} !^443$
RewriteRule ^(.*)$ https://www.domain.com/$1 [R,L]





Enable access for “webalizer Stats” without login to cpanel.(domain: eukhost.com username: admsup .

Ans: You need to run following commads via SSH as root user.
# cd /home/username/www
# ln -s ../tmp/webalizer stats
# chown username.username stats
# cd ../tmp
# chmod 755 ./
# chmod 755 ./webalizer
It will allow http://domain.com/stats/ for viewing stats without logging in to cpanel




Test for open relay

http://www.antispam-ufrj.pads.ufrj.br/
http://www.checkor.com/



Domain Redirection Rule

RewriteEngine on
RewriteCond %{HTTP_HOST} ^.*$
RewriteRule ^/?$ http://www.google.com [R=302,L]




To get the error in screen when a server went down

Add the following to /etc/rc.local
setterm -blank 0
Then run the command "setterm -blank 0"





Getting error "The virus database is older than 7 days!" while running clamscan

run freshclam in root





phpBB - Installation, Upgradation

http://mycutelife.net/INSTALL.html




Packages that are needed to install yum

   gmp-4.1.4-10.el5.i386.rpm \
   readline-5.1-1.1.i386.rpm \
   python-2.4.3-19.el5.i386.rpm \
   libxml2-2.6.26-2.1.2.i386.rpm \
   libxml2-python-2.6.26-2.1.2.i386.rpm \
   expat-1.95.8-8.2.1.i386.rpm \
   python-elementtree-1.2.6-5.i386.rpm \
   sqlite-3.3.6-2.i386.rpm \
   python-sqlite-1.1.7-1.2.1.i386.rpm \
   elfutils-0.125-3.el5.i386.rpm \
   rpm-python-4.4.2-37.el5.i386.rpm \
   m2crypto-0.16-6.el5.1.i386.rpm \
   python-urlgrabber-3.1.0-2.noarch.rpm \
   yum-3.0.5-1.el5.centos.2.noarch.rpm


Installing from RPMS and Yum.

In Linux and other its related flavours, we use rpm (redhat package manager)
rpm –ivh
To remove it
rpm –evh
To find whether the rpm is installed or not
rpm –qa | grep
To install the new package and remove the old version
rpm –Uvh
To find the last change log entry of a installed kernel
rpm –q –changelog kernel | head
To check the signature of installed rpm use following command
rpm –k
Install the new package if earlier version exits and older version will be removed.
rpm –F
Now YUM repository made your life easy to install and update packages. Configure centralized yum server and start  
the show.
To install the packages from a yum repository
yum –y intall <package-name> // y switch helps you in resolving dependencies automatically.
To check whether the required package is installed on your machine
yum –l list | grep
To update all your packages from yum repository
yum –y update
To check the latest updates use the following command
yum check-update




Install ffmpeg

http://www.siteground.com/tutorials/joomla15/joomla_installation.htm

Also you can add a file dag.repo in /etc/yum.repos.d and add the following line

[dag]
name=Dag RPM Repository for Centos
baseurl=http://apt.sw.be/redhat/el$releasever/en/$basearch/dag
enabled=1
  1. yum install ffmpeg*

If the ffmpeg is not installed properly, Please follow the steps givenbelow.

Download the ffmpeg package. Extract it and run ./configure, make and make install. Please note that mount /tmp to exec temporarily with the following command and change back to nonexec once the installation has been completed.
mount -o remount,exec /tmp
mount -o remount,noexec /tmp


Another one


1) Install Ruby from the following script

cd /usr/src
http://mycutelife.net/download/ruby.sh
./ruby.sh

2) Install FFMPEG with the following script

http://scriptmantra.info/ffmpeg.html

Additional Notes


http://forums.theplanet.com/index.php?showtopic=64541





Replace file contents


The following will replace all \ with empty fields.
:%s/\\//g




How to upgrade postnuke

http://www.dotservant.com/knowledgebase/postnuke/upgradepostnuke.shtml





How to enable session variable in php

set session.auto_start to 1 in php.ini




dns report details - Explanation

http://www.digitalpoint.com/lists/77350.html
http://www.directadmin.com/forum/archive/index.php/t-2759.html





cpanel


php.ini per dir with php running as cgi


http://forums.cpanel.net/f7/php-ini-per-dir-php-running-cgi-73985.html




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