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Category: 16.04

  • How to find files on linux OS ( distributions )

    How to find files on linux OS ( distributions )

    find files on linux

    If you are working on Linux OS, finding files effectively always a tricky part.

    Like find files greater than 500 MB, find files which are created 2 days ago, find and delete all files recursively which are greater than specific date.

    Lets learn these simple linux tricks to work with files.

    How to find files or directory in Linux?

    For Files command: 

    find /path/to/directory -name "*.txt" -type f

    For Directory

    find /path/to/directory -name "nameOfDirectory" -type d

    In the above commands only type argument is changed from f to d. f represents for file and d represents for directory.

    How to find files which are greater than specific size?

    find /path/to/directory -type f -size +1024M

    How to find files which are created after number of days?

    find /path/to/directory -mindepth 1 -mtime +5 -size +700M

    How to delete files after finding files?

    Method 1:

    find /path/to/directory -mindepth 1 -mtime +5 -size +700M -delete

    –mindepth is for level

    –mtime for number of days

    –size is for file size greater than or equal to.

    Method 2:

    find . -name "*.done" -type f -print0 | xargs -0 rm -f

    How to find files and set permission to 644 or 664?

    find . -type f -print0 | xargs -0 chmod 0644

    How to find all directory and set permission to 755 or 775?

    find . -type d -print0 | xargs -0 chmod 0755

    This is how you can work with find command. You can always check for man for more arguments.

  • How to create CSR ( Certificate Signing Request ) for new SSL or to renew SSL?

    How to create CSR ( Certificate Signing Request ) for new SSL or to renew SSL?

    What is SSL?

    SSL (Secure Sockets Layer) is a standard security protocol for establishing encrypted connection between a web server and client browser in communication.

    The usage of SSL technology ensures that all data transmitted between the web server and clients browser remains encrypted.

    To get the SSL from Certificate Authorities, you must need to provide the CSR to them and Certificate Authorities will sign the certificate provided by you. CSR contains the information related to Country, State, Locality, Organisation, Organisation Unit, Common Name – Domain Name and email address as well as public key.

    Let’s learn how to generate the CSR?

    Step 1: Generate the private key first. If you are renewing the SSL this step is not required. To generate the private key use below mentioned command.

    surya@x ~/ » openssl genrsa -out blog.suryaelite.com.key 4096

 1 ↵
Generating RSA private key, 4096 bit long modulus
................................++
.........++
e is 65537 (0x010001)

    2048 or higher bit private key recommended. I have used 4096 bit.

    Step 2: Now generate the CSR by using below command.

     

    surya@x ~/ » openssl req -new -key blog.suryaelite.com.key -out blog.suryaelite.com.csr 


You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IN
State or Province Name (full name) [Some-State]:HR
Locality Name (eg, city) []:Gurgaon
Organization Name (eg, company) [Internet Widgits Pty Ltd]:SuryaElite
Organizational Unit Name (eg, section) []:blog
Common Name (e.g. server FQDN or YOUR name) []:blog.suryaelite.com 
Email Address []:surya@suryaelite.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:Surya Elite Pvt. Ltd.

    Now you will have two files, one is private key and second one is CSR. Not you need to send the CSR file to Certificate Authority and then Certificate Authority will sign the Certificate and send you the Certificate.

    Now you need to apply the SSL to the web server you are using NGINX or Apache. So this is how you can generate the CSR File.

  • How to decode CSR (Certificate Signing Request) ?

    How to decode CSR (Certificate Signing Request) ?

    What is CSR?

    Certificate Signing Request
    Certificate Signing Request is encrypted piece of code which is going to used for generating the SSL Certificate for your domain name.

     

    CSR contains the information about Country, State, Location, Organisation Name, Common Name ie Domain Name , Email Address and Public Key.

    Lets see how to extract the information from the CSR file?

    How to extract information from the CSR?

    surya@x ~/ » openssl req -in blog.suryaelite.com.csr -text -noout

    How to verify the signature of CSR?

    surya@x ~/ » openssl req -in blog.suryaelite.com.csr -noout -verify

    To which company certificate is issued to?

    surya@x ~/ » openssl req -in blog.suryaelite.com.csr -noout -subject

    How to extract Public Key from CSR?

    surya@x ~/ » openssl req -in blog.suryaelite.com.csr -noout -pubkey

    This is how you can extract the various information from the CSR file.

  • AWS – NDB – Ubuntu – Add separate location for MySQL temporary (tmp) storage

    AWS – NDB – Ubuntu – Add separate location for MySQL temporary (tmp) storage

    aws_mysql_disk_addition

    By default MySQL uses the system default location used for temporary file storage, which is usually /tmp, /var/tmp, or /usr/tmp. In Ubuntu its /tmp. It’s good practice to specify separate location for MySQL, if you want to prevent System restart. If tmp location is on separate location then only MySQL restart will needed in case of any disk increase needed in future.

    Step 1: Create new EBS Volume by Login to Console and Click on EC2 Dashboard, then click on “Volumes”

    Step 2: Fill the details of Volume and click on create and the new Volume will be created within few seconds.

     

    Step 3: Attach the newly created volume to the Instance.

    Step 4: Check if the volume is attached or not by going to EC2 dashboard and clicking on that particular instance. You can also check by going to Volume stats as well.

    Step 5: Login to machine by your key or password.

    Step 6: Format Volume to ext4 and then mount it and make fstab entry as well.

    root@x:/mnt: lsblk
NAME    MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
xvda    202:0    0    40G  0 disk 
└─xvda1 202:1    0    40G  0 part /
xvdb    202:16   0   400G  0 disk /mnt/data
xvdf    202:80   0   200G  0 disk 


root@x: mkfs.ext4 /dev/xvdf
mke2fs 1.42.9 (4-Feb-2014)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
13107200 inodes, 52428800 blocks
2621440 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
1600 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks: 
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
    4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done     


root@x: mkdir /mnt/xvdf
root@x:/mnt: sudo mount /dev/xvdf /mnt/xvdf/
root@x: mkdir /mnt/xvdf/tmp_mysql
root@x:/mnt/xvdf# chown -Rf mysql:mysql /mnt/xvdf/tmp_mysql
root@x:/var: ln -s /mnt/xvdf/tmp_mysql/ /var/tmp_mysql

    Step 7: Now put the tmp_dir setting in /etc/my.cnf

    [mysqld]
tmpdir = /var/tmp_mysql

    Step 8: Restart the MySQL and check for setting by Login to MySQL and executing below mentioned Query

    root@x:/: sudo service mysql restart

     

    mysql> SHOW VARIABLES LIKE 'tmpdir';

    This is how you can change the temporary directory in AWS hosted Ubuntu Linux environment.

     

  • Ubuntu 16.04 – Cisco VPN Client installation

    Ubuntu 16.04 – Cisco VPN Client installation

    cisco_vpn_client

    On Ubuntu 14.04 only sudo apt-get install network-manager-vpnc was working. But for Ubuntu 16.04 you need to install network-manager-vpnc-gnome as well.

    Step 1: Open Terminal
    Step 2: run below command to install the cisco client

    sudo apt-get install network-manager-vpnc network-manager-vpnc-gnome

    Step 3: Click on the “Network Icon” on toolbar, then click “Edit Connections”
    Step 4: Click on “Add” Button
    Step 5: Choose “Cisco Compatible VPN (vpnc)”, click on “Create”
    Step 6: Fill the below details on VPN Tab

    • Gateway: VPN IP 199.229.XXX.XXX
      UserName
    • UserPassword
    • GroupName
    • GroupPassword

    Step 7: Click on Save

    VPN Setup has been completed.

    To connect VPN, click on the Network Icon on toolbar. Click on VPN Connections. Choose the VPN which you have recently created.

    Please make sure, you are on different network to connect VPN.