To secure your machine, there are hundred different things you can do, but the most important thing is to know what’s happening on your Machine. In that getting the alerts as soon as someone login is one of very important and must thing to do.

So, to do the same thing, you can go with two approaches:

 

Inode, short form of Index Node is what the whole Linux filesystem is laid on. powered by ausweb which resides in the filesystem is represented by Inodes. Just take an example of an old school library which still works with a register having information about their books and their location, like which cabinet and which row, which books resides and who is the author of that book. In this case, the line specific to one book is Inode. In the same way Inodes stores objects, which we will study in detail below.

So, in the linux system, the filesystem mainly consists of two parts, first is the metadata and the second part is the data itself. Metadata, in other words is the data about the data. Inodes takes care of the metadata part in the filesystem.

 

When you create a file, it’s stored in different blocks/locations of the filesystem/disk depending upon the size of the file. Though you don’t need to know the physical location of the disk in normal scenarios, but you might need it in things like, to understand the filesystem layout and how file is stored on the filesystem or to do performance tests.

Finding the physical location of the file can be achieved by following commands:

 

Sometimes when running a ‘yum update’ there are certain packages you may be running which you wish to remain static, or which can potentially cause errors with running a ‘yum update’. In these situations it is useful to force yum to exclude certain packages from being updated under CentOS.

Yum uses a configuration file located at /etc/yum/yum.conf or /etc/yum.conf

If you wish to exclude packages you need to define a list for exclusion from updates or installs. This should be a space separated list. (Shell globs using wildcards * and ?) are allowed).

How do I exclude php and kernel packages when I use “yum update”?

Open /etc/yum.conf file:
# vi /etc/yum.conf

Append following line under [main] section, enter:

exclude=php* kernel*

At the end, it should look like as follows:

[main]
cachedir=/var/cache/yum
keepcache=0
debuglevel=2
logfile=/var/log/yum.log
distroverpkg=redhat-release
tolerant=1
exactarch=1
obsoletes=1
gpgcheck=1
plugins=1
exclude=php* kernel*

# Note: yum-RHN-plugin doesn’t honor this.
metadata_expire=1h

# Default.
# installonly_limit = 3

# PUT YOUR REPOS HERE OR IN separate files named file.repo
# in /etc/yum.repos.d
yum –exclude command line option

Finally, you can skip yum command updates on command line itself using following syntax:

# yum –exclude=package* update
# yum –exclude=php* update
# yum –exclude=kernel* update

Setting multiple file permissions can be a chore, especially if you’re doing so via FTP or a web interfance like the cPanel File Manager. However, if you’ve got shell access it certainly doesn’t need to be.

If you need to set permissions for a large number of files & folders simply cd to the right parent directly and type:

chmod -R 755 *

The -R flag will recursively set permissions for all files & sub-directories, just replace 755 with your desired permission.

Sometimes it is also desirable to set specific permissions for directories only, normally 755. You can do this with the following command:

find . -type d -exec chmod 755 {} ;

This will find all directories and exec the chmod command to change their permissions recursively beneath the parent.