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How to Install and Setup LXC Linux Containers on CentOS / RHEL / Ubuntu

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<u><span style="color: red;"><i>Install and Setup LXC Linux Containers on <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">CentOS </a>/ <a href="http://www.hackthesec.co.in/search/label/RHEL" target="_blank">RHEL</a> / <a href="http://www.hackthesec.co.in/search/label/Ubuntu" target="_blank">Ubuntu</a></i></span></u></h1>
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LXC stands for Linux Containers.</div>
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Linux containers are light-weight “<b><a href="http://www.hackthesec.co.in/search/label/virtualization" target="_blank">virtualization</a></b>” methods that runs multiple virtual units simultaneously on a single control host on a single Linux kernel.</div>
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The Linux kernel contains cgroups for resource isolation (CPU, memory, block I/O, network, etc, ), which does not require starting any virtual machines.<br />
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Cgroups also provides namespace isolation to completely isolate application view of the operating environment, including process trees, networks, userids and mounted filesystems.</div>
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LXC is open source software and licensed under GNU LGPLv2.1+ license.</div>
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Containers actually make use of kernel features called namespaces, cgroups, and chroots, to carve off a contained area.</div>
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So, the end result of LXC looks much like a virtual machine, but without any hypervisor.</div>
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<span style="color: #0b5394;"><u>1. Pre-req for LXC Install</u></span></h3>
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Before you install LXC, make sure your system is up-to-date using yum update as shown below.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">yum </span><span style="color: lime; font-size: medium;">update</span></span></pre>
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LXC is dependent on two libraries; libpcap and libcgroup. This also requires busybox and bridge utilities.</div>
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Install the following required packages for our LXC install.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">yum install </span><span style="color: lime; font-size: medium;">libcap-devel libcgroup busybox wget bridge-utils</span></span></pre>
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Let us make sure we got all the compilers and related development tools that are required to compile and install any software from source code.</div>
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<u><span style="color: #0b5394;">2. Download LXC Linux Containers</span></u></h3>
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Download the latest version of the LXC from <a href="https://linuxcontainers.org/lxc/downloads/" style="color: #dd0000; margin: 0px; padding: 0px; word-wrap: break-word;">Linux Containers Project</a>.</div>
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Use wget to download the tar ball of the latest stable version of LXC to your machine as shown below.</div>
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If you get a certificate related error message while using the above wget, then use the no-check-certificate option as shown below.</div>
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Alternatively, if you prefer, you can also use git clone to download the latest development version or stable version as shown below.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">git clone</span><span style="color: white; font-size: medium;"> git://github.com/lxc/lxc -b {branch}</span></span></pre>
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In the above command, the {branch} can either be “master” for the current development branch, or “stable-1.0″ for the stable update branch of the 1.0 version.</div>
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<u><span style="color: #0b5394;">3. Configure Bridged Adapter</span></u></h3>
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Next, create a bridged adapter and configure the static IP on the bridged adapter as shown in the following ifcfg-eth0 example. Ensure your physical adapter points to this bridged adapter in ifcfg-eth0.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$</span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;"> cd /etc/sysconfig/</span><span style="color: lime; font-size: medium;">network-scripts</span><span style="color: white; font-size: medium;">

</span></span><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$</span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;"> vi </span><span style="color: lime; font-size: medium;">ifcfg-br0</span><span style="color: white; font-size: medium;">

DEVICE="br0"
BOOTPROTO="static"
IPADDR="xxx.xxx.xxx.xxx"
NETMASK="255.255.255.xxx"
ONBOOT="yes"
TYPE="Bridge"
NM_CONTROLLED="no"</span></span></pre>
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Replace all the “xxx” in the above file with the values that matches your ip-address and networkmask. For example, change the IPADDR value in the above file to the ip-address of your machine.</div>
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<u><span style="color: #0b5394;">4. Install LXC Linux Container</span></u></h3>
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Next, untar the LXC tar ball, that we downloaded earlier, execute the ./configure, and do make and make install, to install the LXC on your system as shown below.</div>
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By default, this will install all the lxc binaries under /usr/local/bin directory.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">tar xvfz </span><span style="color: lime; font-size: medium;">lxc-1.1.5.tar.gz</span><span style="color: white; font-size: medium;">

</span></span><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">make && make install</span></span></pre>
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The following are few of the last few lines from the output for the above ./configure command.</div>
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...
...
config.status: creating src/python-lxc/setup.py
config.status: creating src/lua-lxc/Makefile
config.status: executing depfiles commands
</span><span style="color: lime; font-size: medium;">config.status: executing default commands
</span><span style="color: white; font-size: medium;">----------------------------
Environment:
 - compiler: gcc
 - distribution: <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">centos</a>
</span><span style="color: lime; font-size: medium;"> - init script type(s): sysvinit
</span><span style="color: white; font-size: medium;"> - rpath: no
 - GnuTLS: no
</span><span style="color: lime; font-size: medium;"> - Bash integration: yes
</span><span style="color: white; font-size: medium;">Security features:
 - Apparmor: no
</span><span style="color: lime; font-size: medium;"> - Linux capabilities: yes
</span><span style="color: white; font-size: medium;"> - seccomp: no
 - SELinux: no
 - cgmanager: no
Bindings:
 - lua: no
 - python3: no
Documentation:
 - examples: yes
 - API documentation: yes
 - user documentation: no
Debugging:
 - tests: no
</span><span style="color: lime; font-size: medium;"> - mutex debugging: no
</span><span style="color: lime; font-size: medium;">Paths:
</span><span style="color: lime; font-size: medium;"> - Logs in configpath: no</span></span></pre>
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The following are the last few lines from the output for the above make command.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">make</span><span style="color: white; font-size: medium;">
...
Building full member lists recursively...
Adding members to member groups.
...
</span><span style="color: lime; font-size: medium;">Generating style sheet...
</span><span style="color: white; font-size: medium;">Generating index page...
</span><span style="color: lime; font-size: medium;">Generating page index...
</span><span style="color: white; font-size: medium;">Generating example documentation...
Generating file sources...
</span><span style="color: lime; font-size: medium;">Generating code for file /usr/save/lxc-1.1.5/src/lxc/attach_options.h...
</span><span style="color: white; font-size: medium;">Generating code for file /usr/save/lxc-1.1.5/src/lxc/lxccontainer.h...
Generating code for file /usr/save/lxc-1.1.5/src/lxc/lxclock.h...
</span><span style="color: lime; font-size: medium;">Generating file documentation...
Generating docs for file /usr/save/lxc-1.1.5/src/lxc/attach_options.h...</span><span style="color: white; font-size: medium;">
...
Generating file member index...
make[2]: Leaving directory `/usr/save/lxc-1.1.5/doc/api'
make[2]: Entering directory `/usr/save/lxc-1.1.5/doc'
...
</span><span style="color: lime; font-size: medium;">Making all in hooks
make[1]: Entering directory `/usr/save/lxc-1.1.5/hooks'
make[1]: Nothing to be done for `all'</span><span style="color: white; font-size: medium;">.
...</span></span></pre>
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The following are the last few lines from the output for the above make install command.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">make install</span><span style="color: white; font-size: medium;">
...
Making install in hooks
make[1]: Entering directory `/usr/save/lxc-1.1.5/hooks'
 /bin/mkdir -p '/usr/local/share/lxc/hooks'
</span><span style="color: lime; font-size: medium;"> /usr/bin/install -c clonehostname mountecryptfsroot ubuntu-cloud-prep squid-deb-proxy-client '/usr/local/share/lxc/hooks'
</span><span style="color: white; font-size: medium;">...
/bin/mkdir -p /usr/local/var/lib/lxc
/bin/mkdir -p /usr/local/var/cache/lxc
 /bin/mkdir -p '/usr/local/lib/pkgconfig'
</span><span style="color: lime; font-size: medium;"> /usr/bin/install -c -m 644 lxc.pc '/usr/local/lib/pkgconfig'
</span><span style="color: white; font-size: medium;">...</span></span></pre>
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<u><span style="color: #0b5394;">5. Create Soft Link for LXC Shared Libraries</span></u></h3>
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Execute lxc-info to verify that the LXC is installed successfully. If everything is installed properly, we’ll see a message saying that the give container name (for example, test) doesn’t exist. We have not created any container at this stage. We just want to make sure this command is not throwing any shared library related errors.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">lxc-info --name test</span><span style="color: white; font-size: medium;">
test doesn't exist</span></span></pre>
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Depending on how things on configured on your system, you might also get the following liblxc.so.1 library related error message.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">lxc-info --name test
</span><span style="color: lime; font-size: medium;">lxc-info: error while loading shared libraries: liblxc.so.1: cannot open shared object file: No such file or directory</span></span></pre>
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In this case, to fix it, create a link called libxc.so.1 as shown below, which will point to the correct version of the liblxc.so.x.x.x file.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">ln -s </span><span style="color: lime; font-size: medium;">/usr/local/lib/liblxc.so.1.1.5 /lib64/liblxc.so.1</span><span style="color: white; font-size: medium;">

</span></span><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: white; font-size: medium;">ls -l /lib64/liblxc.so.1
</span><span style="color: lime; font-size: medium;">lrwxrwxrwx. 1 root root 30 Jan 20 09:17 /lib64/liblxc.so.1 -> /usr/local/lib/liblxc.so.1.1.5</span></span></pre>
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<u><span style="color: #0b5394;">6. Verify LXC Setup and Configuration</span></u></h3>
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Next, you can also execute the lxc-checkconfig to verify that your lxc environment is setup correctly.</div>
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The following will have output in four different sections: 1) Namespaces, 2) Control Groups 3) Misc and 4) Checkpoint/Restore. Partial output is shown below.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: white; font-size: medium; line-height: 1.3em;">root@hackthesec:~$ </span><span style="background-color: transparent; line-height: 15.6px;"><span style="color: lime; font-size: medium;">lxc-checkconfig</span><span style="color: white; font-size: medium;">
Kernel configuration not found at /proc/config.gz; searching...
</span><span style="color: lime; font-size: medium;">Kernel configuration found at /boot/config-2.6.32-431.el6.x86_64
</span><span style="color: white; font-size: medium;">--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: enabled
</span><span style="color: lime; font-size: medium;">User namespace: enabled
</span><span style="color: white; font-size: medium;">Network namespace: enabled
</span><span style="color: lime; font-size: medium;">Multiple /dev/pts instances: enabled
</span><span style="color: white; font-size: medium;">--- Control groups ---
Cgroup: enabled
Cgroup namespace: enabled
Cgroup device: enabled
Cgroup sched: enabled
Cgroup cpu account: enabled
..
--- Misc ---
</span><span style="color: lime; font-size: medium;">Veth pair device: enabled
</span><span style="color: white; font-size: medium;">Macvlan: enabled
Vlan: enabled
Bridges: enabled
</span><span style="color: lime; font-size: medium;">Advanced netfilter: enabled
</span><span style="color: white; font-size: medium;">..
</span><span style="color: lime; font-size: medium;">--- Checkpoint/Restore ---
CONFIG_EVENTFD: enabled
CONFIG_EPOLL: enabled</span><span style="color: white; font-size: medium;">
..
Note : Before booting a new kernel, you can check its configuration
</span><span style="color: lime; font-size: medium;">usage : CONFIG=/path/to/config /usr/local/bin/lxc-checkconfig</span></span></pre>
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If everything is configured properly on your system, in the above output, all of the options in the above groups should say “enabled”.</div>
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How to Install and Setup LXC Linux Containers on CentOS / RHEL / Ubuntu

Install and Setup LXC Linux Containers on CentOS / RHEL / Ubuntu LXC stands for Linux Containers. Linux containers are light-weight ...

How to Move Running Command to Background in Linux

[1]+  Stopped          tar czf random-file.tar.gz /var/log</span><span style="font-size: 0.9em;">
</span></pre>
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<span style="font-family: "georgia" , "times new roman" , serif;">Now type <red>bg</red> command on terminal, This will start last paused command in background by appending & in command.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;">root@hackthesec:~$ bg

[1]+ tar czf random-file.tar.gz /var/log &</span><span style="font-size: 0.9em;">
</span></pre>
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<span style="color: #0b5394;">List Running Commands in Background</span></h2>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: "georgia" , "times new roman" , serif;">To list all jobs running in background use jobs command. It will show all running commands with their job id.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;">root@hackthesec:~$ jobs

[1]+  Running                 tar czf random-file.tar.gz /var/log &</span><span style="font-size: 0.9em;">
</span></pre>
<h2 class="heading1" style="background-color: white; border: 0px; font-family: 'Roboto Slab'; font-size: 24px; font-weight: bolder; line-height: 34px; margin: 45px 0px 12px; opacity: 1; outline: 0px; padding: 0px; transition: opacity 0.24s ease-in-out; vertical-align: baseline; visibility: visible;">
<span style="color: #0b5394;">Move Background Commands to Foreground (Terminal)</span></h2>
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<span style="font-family: "georgia" , "times new roman" , serif;">Now, If you need to any background jobs to move to foreground. Use <b><red>fg</red> command</b> with job id and this will move background command with that job id to terminal. Job id can be found using jobs command as showing in above example.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;">root@hackthesec:~$ fg 1</span></pre>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><a href="http://www.hackthesec.co.in/" target="_blank">www.hackthesec.co.in</a>
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How to Move Running Command to Background in Linux

Move Running Command to Background in Linux For example you are taking a backup of large number of files, You have started command on ...

Unpacking or uncompressing gz files under Linux and UNIX systems

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<span style="color: red;"><u><i>Extract .gz file in linux</i></u></span></h1>
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The .gz file extension are created using Gzip program which reduces the size of the named files using Lempel-Ziv coding (LZ77). gunzip / gzip is software application used for file compression. gzip is short for GNU zip; the program is a free software replacement for the compress program used in early Unix systems.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGXXBedKE2dlCxicQnuV-0CIJp2gsrChvWlbZBK9huQgthY8pG4lz7q3JiYj5JIA5vytX7i6quN2FMlLUZLDoKrGGyMVxgjZkz6Z3UxCmTo133CcLEgapjAxFtwsD1kkexyjkQr295uj7U/s1600/compressing_www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="136" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGXXBedKE2dlCxicQnuV-0CIJp2gsrChvWlbZBK9huQgthY8pG4lz7q3JiYj5JIA5vytX7i6quN2FMlLUZLDoKrGGyMVxgjZkz6Z3UxCmTo133CcLEgapjAxFtwsD1kkexyjkQr295uj7U/s320/compressing_www.hackthesec.co.in.jpg" width="320" /></a></div>
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Each file is replaced by one with the extension .gz, while keeping the same ownership modes, access and modification times.</div>
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To expand i.e. to Unpacking or <b>uncompressing </b>gz files you need to use gunzip program Or gzip -d or zcat program:</div>
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Using <b>gunzip </b>command:</div>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="font-family: monaco, courier new, dejavu sans mono, bitstream vera sans mono, monospace; font-size: medium;"><span style="line-height: 19px; white-space: pre-wrap;"><span style="color: white;">$ </span><span style="color: lime;">gunzip file.gz</span><span style="color: white;">
$ ls file</span></span></span></pre>
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Using gzip -d command:</div>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="font-family: monaco, courier new, dejavu sans mono, bitstream vera sans mono, monospace; font-size: medium;"><span style="line-height: 19px; white-space: pre-wrap;"><span style="color: white;">$ </span><span style="color: lime;">gzip -d</span><span style="color: white;"> file.gz
$ ls file</span></span></span></pre>
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If file extension is tar.gz, type the command:</div>
<pre style="background: rgb(54, 54, 54); border-radius: 7px; border: 1px solid rgb(221, 221, 221); font-stretch: inherit; margin-bottom: 15px; margin-top: 15px; overflow-x: auto; overflow-y: hidden; padding: 18px 20px; vertical-align: baseline;"><span style="font-family: monaco, courier new, dejavu sans mono, bitstream vera sans mono, monospace; font-size: medium;"><span style="line-height: 19px; white-space: pre-wrap;"><span style="color: white;">$ </span><span style="color: lime;">tar -zxvf</span><span style="color: white;"> file.tar.gz</span></span></span></pre>
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Please note that <b>gunzip </b>can currently decompress files created by <b>gzip</b>, <b>zip</b>, <b>compress</b>, compress -H or pack programs.</div>
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<span style="color: #0b5394;"><u>See also:</u></span></h2>
<ul style="background-color: white; color: #111111; font-family: Arial, 'Helvetica Neue', Helvetica, sans-serif; font-size: 16px; line-height: 27px; list-style-type: square; margin: 0px 0px 27px 27px; padding: 0px; word-wrap: break-word;">
<li style="margin: 0px; padding: 0px; word-wrap: break-word;"><a href="http://www.hackthesec.co.in/p/compressing-files-under-linux-or-unix.html" target="_blank">Compressing/expanding files under Linux or UNIX command cheat sheet</a></li>
<li style="margin: 0px; padding: 0px; word-wrap: break-word;"><a href="http://www.hackthesec.co.in/">www.hackthesec.co.in</a></li>
<li style="margin: 0px; padding: 0px; word-wrap: break-word;"><a href="http://www.twitter.com/hackthesecurity">www.twitter.com/hackthesecurity</a></li>
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Unpacking or uncompressing gz files under Linux and UNIX systems

Extract .gz file in linux The .gz file extension are created using Gzip program which reduces the size of the named files using Lem...

How To Implement Access Control List (ACL) For CentOS/RHEL 7

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<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
<span style="color: red; font-size: large;"><u><i>Implement Access Control List (ACL) For <a href="http://www.hackthesec.co.in/search/label/centos7" target="_blank">CentOS 7</a>/<a href="http://www.hackthesec.co.in/search/label/Rhel7" target="_blank">RHEL7</a></i></u></span></h1>
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<span style="color: #0b5394; font-size: large;">What is Access Control List (ACL)?</span></h2>
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Files and directories or folders have permission sets for the owner of the file along with the group associated with that file and all other users of that system. But these permission sets have some limitations. For example, different permissions cannot be configured for different users. Thus, Access Control Lists (ACLs) were implemented.</div>
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ACLs can be configured as follows<br /></div>
<ul style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 25.6px; margin: 0px 0px 15px 30px; padding: 0px;">
<li style="box-sizing: border-box; list-style: disc;">Per user</li>
<li style="box-sizing: border-box; list-style: disc;">Per group</li>
<li style="box-sizing: border-box; list-style: disc;">For users not in the user group for the file</li>
</ul>
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ACL  provides an additional flexible permission mechanism for file system on a Linux system. It enhance the traditional <a href="http://www.hackthesec.co.in/search/label/Unix" target="_blank">UNIX </a>file permissions for files & folder. With ACL, you can give permissions for any user or any group with fine-grained access rights.</div>
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ACLs can be configured per user, per group or via the effective rights mask. These permissions then can be apply to an individual user or a group, and also you can use the same as rwx (Read, Write, Execute) found in regular file / folder permissions.</div>
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ACLs requires kernel support and your kernel musk support <a href="http://www.hackthesec.co.in/search/label/ACL_Permission" target="_blank">ACL </a>in order to implement ACL on your Linux distribution. Along with support in the kernel, the acl package is also required to implement ACLs. Acl package contains the utilities used to add, modify, remove, and retrieve ACL information from a file / folder.</div>
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<span style="color: #0b5394; font-size: large;">Why CentOS Linux?</span></h2>
<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
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CentOS Linux is a community-supported distribution derived from sources freely provided to the public by Red Hat for Red Hat Enterprise Linux (<a href="http://www.hackthesec.co.in/search/label/RHEL" target="_blank">RHEL</a>). As such, CentOS Linux aims to be functionally compatible with <a href="http://www.hackthesec.co.in/search/label/Rhel7" target="_blank">RHEL</a>. The <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">CentOS </a>Project mainly changes packages to remove upstream vendor branding and artwork. CentOS Linux is no-cost and free to redistribute. Each CentOS version is maintained for up to 10 years (by means of security updates — the duration of the support interval by Red Hat has varied over time with respect to Sources released). A new CentOS version is released approximately every 2 years and each CentOS version is periodically updated (roughly every 6 months) to support newer hardware. This results in a secure, low-maintenance, reliable, predictable and reproducible Linux environment.</div>
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You can download CentOS from <a href="https://wiki.centos.org/Download" style="-webkit-tap-highlight-color: transparent; background: 0px 0px; box-sizing: border-box; color: #ff5a00; text-decoration: none; transition: background 0.2s ease-out, color 0.2s ease-out;">here</a>. You can directly download the ISO file format disk image from <a href="http://buildlogs.centos.org/rolling/7/isos/x86_64/CentOS-7-x86_64-DVD.iso" style="-webkit-tap-highlight-color: transparent; background: 0px 0px; box-sizing: border-box; color: #ff5a00; text-decoration: none; transition: background 0.2s ease-out, color 0.2s ease-out;">here</a>.</div>
</h1>
<h2 style="background-color: white; box-sizing: border-box; font-weight: 400; margin: 0px 0px 1.3em; padding: 0px;">
<span style="color: #134f5c; font-size: large;"><span style="font-family: Oswald, Lato, Arial, sans-serif;"><span style="line-height: 35px;"><u>Prerequisites</u></span></span></span><span style="font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em;">Before beginning, you must know whether your Linux OS kernel supports ACL or not.</span></h2>
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First, switch to root user. This is not required if your current local user have sudo privileges. This is only for this tutorial. Do not practise this for regular system administration.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[centos@hackthesec]#</span><span style="color: lime;"> su - </span></span></span></pre>
<div>
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Type your root user password for continue.</div>
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To know whether your kernel supports ACL or not, type the following command in a terminal.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> cat /boot/config-4.1.6-1.el6.elrepo.x86_64 | grep _ACL
</span></span></span></pre>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
<span style="line-height: 28.8px;">After issuing the above command, you will see something like this which indicates that your kernel has the support for ACL.</span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIi2x0ycBCGtjAIFDoExd04UN41bjWMVbDEFXQA7nwqiDmzJLLY0hqA1K66cOhmrNJzOwmQ3yIW89RKcEl6tZRkxdPR1H6IBCbloVQIrwC-7Yz290DDNlU-wkVIrOSwop2OoeZBdmcTw4Y/s1600/ACL_Result-www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiIi2x0ycBCGtjAIFDoExd04UN41bjWMVbDEFXQA7nwqiDmzJLLY0hqA1K66cOhmrNJzOwmQ3yIW89RKcEl6tZRkxdPR1H6IBCbloVQIrwC-7Yz290DDNlU-wkVIrOSwop2OoeZBdmcTw4Y/s1600/ACL_Result-www.hackthesec.co.in.png" /></a></div>
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<span style="line-height: 28.8px;">Now, let’s check whether we have the ACL package installed on our system or not. To check such case, issue the below command in a terminal.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> rpm -qa | grep acl</span></span></span></pre>
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<span style="line-height: 28.8px;">You you will see something like below image.</span></div>
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_A1ehPxvggr1zMMLLuhmgi48ZgbBj1LhDvO8jnD27xeOjfM6VvXLeinWgtU16XTzW2iNhmmAMWLUXHIHaBve-9UXTw3_KeawuL8AjPmNaiv3QO3UmOXA90V-dbpkiazaVtJAfGTCG8an_/s1600/ACL_grep-www.hackthesec.co.in.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi_A1ehPxvggr1zMMLLuhmgi48ZgbBj1LhDvO8jnD27xeOjfM6VvXLeinWgtU16XTzW2iNhmmAMWLUXHIHaBve-9UXTw3_KeawuL8AjPmNaiv3QO3UmOXA90V-dbpkiazaVtJAfGTCG8an_/s1600/ACL_grep-www.hackthesec.co.in.png" /></a></div>
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<span style="line-height: 28.8px;">If you don’t have ACL package installed on your system, then issue the below command to install ACL package onto your system.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> yum install acl</span></span></span></pre>
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</h1>
<h2 style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 35px; margin: 0px 0px 1.3em; padding: 0px;">
<span style="color: #0b5394; font-size: large;">Let’s Start</span></h2>
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<span style="box-sizing: border-box; font-weight: 700;">Mounting File Systems</span></div>
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Before using any ACLs for a file or directory, the partition for the file or directory must be mounted with ACL support.</div>
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A local file system can be mounted with the following command syntax shown as below.</div>
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</h1>
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<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> mount /dev/sdb /acltest</span></span></span></pre>
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Here, <span style="box-sizing: border-box; font-weight: 700;">/dev/sdb</span> is a disk device block and <span style="box-sizing: border-box; font-weight: 700;">acltest</span> is the folder where it will be mounted for access.</div>
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After that, you need to edit the file <span style="box-sizing: border-box; font-weight: 700;">/etc/fstab</span> for the <span style="box-sizing: border-box; font-weight: 700;">/dev/sdb</span> partition and you need to include the acl as follows. This will mount <span style="box-sizing: border-box; font-weight: 700;">/dev/sdb</span> automatically whenever you are rebooting your system.</div>
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Open the file by using the following command.</div>
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</div>
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</h1>
</div>
</h1>
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<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin: 0px 0px 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> vi /etc/fstab</span></span></span></pre>
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</h1>
<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
<div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
and then type the following on the /etc/fstab file.</div>
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</h1>
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<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> /dev/sdb /acltest ext4 acl 1 2</span></span></span></pre>
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</h1>
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Save & exit from the file /etc/fstab. So, whenever you will reboot, your partition will be mounted automatically with acl support.</div>
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After editing the file we need to remount the partition again. To do so,</div>
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</div>
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</h1>
</div>
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<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin: 0px 0px 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> mount -o remount,acl /dev/sdb</span></span></span></pre>
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</h1>
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<div>
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You can issue the below command to confirm whether your previous remount command worked or not.</div>
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</div>
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</h1>
<h1 class="entry-title" itemprop="headline" style="-webkit-text-stroke-width: 0px; background-color: white; box-sizing: border-box; color: black; font-family: Oswald, Lato, Arial, sans-serif; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 50px; margin: 0px 0px 5px; orphans: auto; padding: 0px; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">
<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: #333333; line-height: 19.2px; margin: 0px 0px 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> mount</span></span></span></pre>
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</h1>
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<div>
<span style="font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 28.8px;"> Now Create a user . and SET password</span></div>
</h1>
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<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> useradd hackthesec1
</span><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> passwd hackthesec1</span></span></span></pre>
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</h1>
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</h1>
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<div>
</div>
<div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
To test acl, we will need at least two users and I will use root and hackthesec1. However you can use different users and it’s up to you.</div>
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First we create a file <span style="box-sizing: border-box; font-weight: 700;">demoacltest.txt</span> in folder <span style="box-sizing: border-box; font-weight: 700;">/acltest </span>folder path location.</div>
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<div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
We will add acl for user hackthesec1 which will allow hackthesec 1user to write /acltest/demoacltest.txt file.</div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
</div>
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</h1>
</div>
</h1>
<h1 class="entry-title" itemprop="headline" style="-webkit-text-stroke-width: 0px; background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 50px; margin: 0px 0px 5px; orphans: auto; padding: 0px; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin: 0px 0px 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> setfacl -R -m u:</span></span><span style="color: white;"><span style="font-size: large;">hackthesec1:rwx /acttest/demoacltest.txt
</span><span style="font-size: medium;">
and for default permission just use this command bellow

</span><span style="font-size: large;">[root@hackthesec]# setfacl -R -m d:u:hackthesec1:rwx /acltest/demoacltest.txt</span></span></span></pre>
</div>
</h1>
<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
<div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
Now if you want to see the file permission just run the bellow command</div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> getfacl</span></span><span style="color: white;"><span style="font-size: large;"> /acttest/demoacltest.txt
</span><span style="font-size: medium;">

Result: - 
#file: acltest/demoacltest.txt
#owner: root
#group: root
#flags: -s-
user::rwx
user::hackthesec1:rwx
group::rwx
mask::rwx
other::---
default:user::rwx
default:user:hackthesec1:rwx
default:group::--x
default:mask::rwx
default:other::--x</span></span></span></pre>
</div>
</h1>
<h2 style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 35px; margin: 0px 0px 1.3em; padding: 0px;">
<span style="color: #0b5394; font-size: large;"><u>Removing any acls</u></span></h2>
<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
To remove all of the currently defined ACLs from a file or folder, issue the below command.</div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
</div>
</h1>
<h1 class="entry-title" itemprop="headline" style="-webkit-text-stroke-width: 0px; background-color: white; box-sizing: border-box; color: black; font-family: Oswald, Lato, Arial, sans-serif; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 50px; margin: 0px 0px 5px; orphans: auto; padding: 0px; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">
</h1>
<br />
<h1 class="entry-title" itemprop="headline" style="-webkit-text-stroke-width: 0px; background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; line-height: 50px; margin: 0px 0px 5px; orphans: auto; padding: 0px; text-align: left; text-indent: 0px; text-transform: none; white-space: normal; widows: 1; word-spacing: 0px;">
<div>
<pre style="background-attachment: scroll; background-clip: initial; background-color: #3c3c3c; background-image: none; background-origin: initial; background-position: 0px 0px; background-repeat: repeat; background-size: initial; border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 19.2px; margin: 0px 0px 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="line-height: 15.6px;"><span style="font-size: large;"><span style="color: white;">[root@hackthesec]#</span><span style="color: lime;"> setfacl -b </span><span style="color: white;">/acltest/demoacltest.txt</span></span></span></pre>
</div>
</h1>
<h1 class="entry-title" itemprop="headline" style="background-color: white; box-sizing: border-box; font-family: Oswald, Lato, Arial, sans-serif; font-weight: 400; line-height: 50px; margin: 0px 0px 5px; padding: 0px;">
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
Here, demoacltest.txt is a file name.</div>
<div style="box-sizing: border-box; font-family: Lato, Arial, sans-serif; font-size: 16px; line-height: 1.8em; margin-bottom: 0.9em; margin-top: 0.9em;">
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</h1>
</div>

How To Implement Access Control List (ACL) For CentOS/RHEL 7

Implement Access Control List (ACL) For CentOS 7 / RHEL7 What is Access Control List (ACL)? Files and directories or folders have per...

Send Email Alert When Hardware Errors Detected

<div dir="ltr" style="text-align: left;" trbidi="on">
<div style="margin-bottom: 0in;">
<span style="color: red; font-size: large;"><i style="color: red; font-weight: bold; text-decoration: underline;">Send Email Alert When Hardware Errors
Detected</i></span></div>
<div style="margin-bottom: 0in;">
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtAmpCzzGIBWU_apJYj-213hyphenhyphensUMg2Ps59KWup0n4uaRzJZmA41rG4KOKjsTS3UwyTkbKfglRLY1t6HnA9Nj9QqmlS_MOdbdq2Mnt-hfVf9-K_zHTPkQOb_vi0EPBrv2KvwoxJjv_mo-5Z/s1600/hardware-bug-www.hackthesec.co.in.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgtAmpCzzGIBWU_apJYj-213hyphenhyphensUMg2Ps59KWup0n4uaRzJZmA41rG4KOKjsTS3UwyTkbKfglRLY1t6HnA9Nj9QqmlS_MOdbdq2Mnt-hfVf9-K_zHTPkQOb_vi0EPBrv2KvwoxJjv_mo-5Z/s1600/hardware-bug-www.hackthesec.co.in.jpg" /></a></div>
<span style="color: red; font-size: large;"><u><b><i><br /></i></b></u></span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# yum install mcelog -y</span></span></pre>
<div style="margin-bottom: 0in;">
<span style="font-size: large;">Default Mcelog cron file is here</span><span style="color: red; font-size: large;"> /etc/cron.hourly/mcelog.cron</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# vi /etc/cron.hourly/mcelog.cron

#!/bin/bash

# do not run if mcelogd is running

service mcelogd status >& /dev/null

[ $? -eq 0 ] && exit 0

# is mcelog supported?

/usr/sbin/mcelog --supported >& /dev/null

if [ $? -eq 1 ]; then

exit 1;

/usr/sbin/mcelog --ignorenodev --filter >> /var/log/mcelog </span></span></pre>
<div>
<span style="line-height: 15.6px;"><b><span style="font-family: "georgia" , "times new roman" , serif; font-size: large;"><br /></span></b></span></div>
<div style="margin-bottom: 0in;">
<span style="font-family: "georgia" , "times new roman" , serif; font-size: large;">After that paste bellow line into you
<b>hardwareerror.sh</b> file.. </span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# touch hardwareerror.sh
</span></span></pre>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="color: lime; font-size: medium;"><span style="line-height: 15.6px;">[root@instructor script]# vi hardwareerror.sh

#!/bin/bash

[ $(grep -c "error" /var/log/mcelog) -gt 0 ] && echo "Hardware Error Found $(hostname) @ $(date)" |

cat /var/log/mcelog | mail -s 'H/w Error' info@hackthesec.co.in

exit 0 </span></span></pre>
<div style="margin-bottom: 0in;">
<span style="color: red;"><span style="font-family: Georgia, Times New Roman, serif; font-size: large;">and run the script through cronjob<br /></span><span style="color: red;">Note : - If your system get any hardware issue then the script will send you a mail other wise you did </span></span></div>
<div style="margin-bottom: 0in;">
<span style="color: red;"></span></div>
<div style="margin-bottom: 0in;">
<span style="color: red;">not get any email... *Only when your system detected any issue*</span></div>
<div style="margin-bottom: 0in;">
<br /></div>
<div style="margin-bottom: 0in;">
<a href="http://www.hackthesec.co.in/" target="_blank">www.hackthesec.co.in</a><br /><a href="http://www.twitter.com/hackthesecurity">www.twitter.com/hackthesecurity</a><br /><a href="http://www.hackthesec.co.in/p/about-us.html">http://www.hackthesec.co.in/p/about-us.html</a></div>
</div>

Send Email Alert When Hardware Errors Detected

Send Email Alert When Hardware Errors Detected [root@instructor script]# yum install mcelog -y Default Mcelog cron file is here /e...

Automated Linux Apache MySQL PHP or Nginx PHP-FPM MYSQL installation and configuration

Automated Linux Apache MySQL PHP or Nginx PHP-FPM MYSQL installation and configuration

Linux Apache MySQL PHP or Nginx PHP-FPM MYSQL This is auto-installer for automatically install and configure apache or nginx with MySQ...

How To Install KDE Plasma 5.5 on Ubuntu 15.10 and 14.04

How To Install KDE Plasma 5.5 on Ubuntu 15.10 and 14.04

KDE Plasma 5.5 on Ubuntu 15.10 & 14.04 KDE is an international free software community producing free and libre software like Plasma...

How To Install eJabberd XMPP Server on Ubuntu 15.10 and 14.04

<div dir="ltr" style="text-align: left;" trbidi="on">
<h2 class="title single-title title20" style="background-color: white; border: 0px; font-family: 'Roboto Slab'; font-size: 28px; line-height: 38px; margin: 0px 0px 5px; opacity: 1; outline: 0px; padding: 0px; transition: opacity 0.24s ease-in-out; vertical-align: baseline; visibility: visible;">
<span style="color: red;"><u><i>eJabberd XMPP Server on Ubuntu 15.10 & 14.04</i></u></span></h2>
<span style="font-size: large;"><br /></span>
<span style="background-color: white;"><span style="font-family: Georgia, Times New Roman, serif; font-size: large;"><span style="line-height: 28px;"><b>ejabberd </b>is an XMPP application server, written mainly in the Erlang programming language. It can run under several Unix-like operating systems such as Mac OS X, GNU/<a href="http://www.hackthesec.co.in/search/label/Linux" target="_blank">Linux</a>, FreeBSD, NetBSD, OpenBSD and OpenSolaris. Additionally, ejabberd can run under Microsoft Windows. The name ejabberd stands for Erlang Jabber Daemon (Jabber being a former name for XMPP) and is written in lowercase only, as is common for daemon software.</span></span></span><br />
<h2 class="heading1" style="background-color: white; border: 0px; font-family: 'Roboto Slab'; font-size: 24px; font-weight: bolder; line-height: 34px; margin: 45px 0px 12px; opacity: 1; outline: 0px; padding: 0px; transition: opacity 0.24s ease-in-out; vertical-align: baseline; visibility: visible;">
<span style="color: #0b5394;">Install eJabberd</span></h2>
<div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="color: white;">$ sudo apt-get install </span><span style="color: lime;">ejabberd</span><span style="color: white;">
</span></span></pre>
</div>
<div>
<h2 class="heading1" style="background-color: white; border: 0px; font-family: 'Roboto Slab'; font-size: 24px; font-weight: bolder; line-height: 34px; margin: 45px 0px 12px; opacity: 1; outline: 0px; padding: 0px; transition: opacity 0.24s ease-in-out; vertical-align: baseline; visibility: visible;">
<span style="color: #0b5394;">Configure eJabberd</span></h2>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;">For this installation we are using domain <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-size: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">demo.hackthesec.co.in</span> in configuration. You may only use localhost for you local system, but for remote server use a domain or sub-domain. So at first I make a host file entry to map </span><span style="font-family: Georgia, 'Times New Roman', serif; font-weight: bold;">demo.hackthesec.co.in</span><span style="font-family: Georgia, Times New Roman, serif;"> with eJabberd server ip address.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); color: white; line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;">$ sudo echo "192.168.10.120 demo.hackthesec.co.in" >> /etc/hosts
</span></pre>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;">Now you need to create admin accounts for your domain. Below commands will create admin accounts for both virtual hosts <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-size: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">localhost</span> and <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-size: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">demo.hackthese.co.in</span>.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="color: white;">$ </span><span style="color: lime;">ejabberdctl register</span><span style="color: white;"> admin localhost password
$ ejabberdctl register admin </span></span><span style="color: white; font-size: large; line-height: 1.3em;">demo.hackthesec.co.in</span><span style="color: white; font-size: large; line-height: 1.3em;"> password</span></pre>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;">Now edit ejabberd configuration file <orange><b>/etc/ejabberd/ejabberd.yml</b></orange> in text editor and add <b>acl </b>for admin user for demo.hackthesec.co.in.</span></div>
<pre class="pretty" style="background: none 0px 0px repeat scroll rgb(240, 240, 240); border-left-color: rgb(116, 183, 63); border-left-width: 3px; border-radius: 5px; border-style: none none none solid; line-height: 1.5em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 8px 20px 8px 18px; vertical-align: baseline;"><span style="font-size: large;">acl:
  admin:
     user:
         - "<span style="color: orange;">admin": "localhost"</span>
         <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">- "admin": "demo.hackthesec.co.in"</span></span><span style="font-size: 0.9em;">
</span></pre>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;">Now add <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-size: inherit; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">im.example.com</span> under hosts section.</span></div>
<pre class="pretty" style="background: none 0px 0px repeat scroll rgb(240, 240, 240); border-left-color: rgb(116, 183, 63); border-left-width: 3px; border-radius: 5px; border-style: none none none solid; line-height: 1.5em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 8px 20px 8px 18px; vertical-align: baseline;"><span style="font-size: large;">hosts:
  - "localhost"
  <span style="border-image-outset: initial; border-image-repeat: initial; border-image-slice: initial; border-image-source: initial; border-image-width: initial; border: 0px; font-weight: 700; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline;">- "</span></span><span style="font-size: large; font-weight: 700; line-height: 1.5em;">demo.hackthesec.co.in</span><span style="font-size: large; font-weight: 700; line-height: 1.5em;">"</span></pre>
<h2 class="heading1" style="background-color: white; border: 0px; font-family: 'Roboto Slab'; font-size: 24px; font-weight: bolder; line-height: 34px; margin: 45px 0px 12px; opacity: 1; outline: 0px; padding: 0px; transition: opacity 0.24s ease-in-out; vertical-align: baseline; visibility: visible;">
<span style="color: #0b5394;">Access eJabberd Web Panel</span></h2>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;">After making all above configuration, let’s restart <b>eJabberd </b>service using following command.</span></div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;"><span style="font-size: large;"><span style="color: white;">$ sudo service </span><span style="color: lime;">ejabberd restart</span><span style="color: white;">
</span></span></pre>
<div style="background-color: white; border: 0px; font-size: 16px; line-height: 28px; margin-bottom: 20px; outline: 0px; padding: 0px; vertical-align: baseline;">
<span style="font-family: Georgia, Times New Roman, serif;"><b>eJabberd </b>admin web panel start on default <b>port 5280</b>. Access access your domain on port 5280 followed by /admin</span></div>
<pre class="pretty" style="background: none 0px 0px repeat scroll rgb(240, 240, 240); border-left-color: rgb(116, 183, 63); border-left-width: 3px; border-radius: 5px; border-style: none none none solid; line-height: 1.5em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 8px 20px 8px 18px; vertical-align: baseline;"><span style="font-size: large;">  http://</span><span style="font-size: large; font-weight: 700; line-height: 1.5em;">demo.hackthesec.co.in</span><span style="font-size: large; line-height: 1.5em;">:5280/admin</span></pre>
</div>
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