Corrected spell and grammar..

courses/level101/linux_basics/command_line_basics.md

@@ -88,8 +88,8 @@ print the working directory.
 The cd command can be used to change the working directory. Using the
 command, you can move from one directory to another.
 
-In the below example, we are initially in the root directory. we have
-then used the cd command to change the directory.
+In the below example, we are initially in the root directory. we then
+used the cd command to change the directory.
 
 ![](images/linux/commands/image3.png)
 
@@ -223,22 +223,22 @@ mv <source_path> <destination_path>
 ```
 
 In this example, we will use the mv command to move the
-"\_test_runner.py" file to "test_directory". In this case, this file
+"\_test_runner.py" file to "test_directory". In this case, this file is 
 already exists in "test_directory". The mv command will just replace it.
 **Do note that the original file doesn't exist in the current directory
-after mv command ran successfully.**
+after the mv command ran successfully.**
 
 ![](images/linux/commands/image26.png)
 
 We can also use the mv command to move a directory from one location to
 another. In this case, we do not need to use the '-r' flag that we did
 while using the cp command. Do note that the original directory will not
-exist if we use mv command.
+exist if we use the mv command.
 
 One of the important uses of the mv command is to rename files and
 directories. Let's see how we can use this command for renaming.
 
-We have first changed our location to "test_directory". We then use the
+We first changed our location to "test_directory". We then use the
 mv command to rename the ""\_test_runner.py" file to "test.py".
 
 ![](images/linux/commands/image29.png)
@@ -268,7 +268,7 @@ to 100 in this file. Each number will be in a separate line.
 ![](images/linux/commands/image21.png)
 
 Do not worry about the above command now. It's an advanced command which
-is used to generate numbers. We have then used a redirection operator to
+is used to generate numbers. We then used a redirection operator to
 push these numbers to the file. We will be discussing I/O redirection in the
 later sections.
 
@@ -282,7 +282,7 @@ other purposes. We will study about other use cases later.
 ![](images/linux/commands/image1.png)
 
 You can try to run the above command and you will see numbers being
-printed from 1 to 100 on your screen. You will need to scroll up to view
+printed from 1 to 100 on your screen. You will need to scroll up to see
 all the numbers.
 
 ### head
@@ -291,12 +291,12 @@ The head command displays the first 10 lines of the file by default. We
 can include additional arguments to display as many lines as we want
 from the top.
 
-In this example, we are only able to see the first 10 lines from the
+In this example, we are only able to see the first 10 lines of the
 file when we use the head command.
 
 ![](images/linux/commands/image15.png)
 
-By default, head command will only display the first 10 lines. If we
+By default, the head command will only display the first 10 lines. If we
 want to specify the number of lines we want to see from start, use the
 '-n' argument to provide the input.
 
@@ -311,7 +311,7 @@ from the end of the file.
 ![](images/linux/commands/image22.png)
 
 By default, the tail command will only display the last 10 lines. If we
-want to specify the number of lines we want to see from the end, use '-n'
+want to specify the number of lines we want to see from the end, use the '-n'
 argument to provide the input.
 
 ![](images/linux/commands/image10.png)

courses/level101/linux_basics/intro.md

@@ -79,7 +79,7 @@ and system utilities. The Linux kernel was independently developed and
 released by Linus Torvalds. The Linux kernel is free and open-source -
 [https://github.com/torvalds/linux](https://github.com/torvalds/linux)
 
-Linux is a kernel and and not a complete operating system. Linux kernel is combined with GNU system to make a complete operating system. Therefore, linux based operating systems are also called as GNU/Linux systems. GNU is an extensive collection of free softwares like compiler, debugger, C library etc.
+Linux is a kernel and it's not a complete operating system. Linux kernel is combined with GNU system to make a complete operating system. Therefore, linux based operating systems are also called as GNU/Linux systems. GNU is an extensive collection of free softwares like compiler, debugger, C library etc.
 [Linux and the GNU  System](https://www.gnu.org/gnu/linux-and-gnu.en.html)
 
 History of Linux -
@@ -92,7 +92,7 @@ the Linux kernel and a package management system. A package management
 system consists of tools that help in installing, upgrading,
 configuring and removing softwares on the operating system.
 
-Software are usually adopted to a distribution and are packaged in a
+Softwares are usually adopted to a distribution and are packaged in a
 distro specific format. These packages are available through a distro
 specific repository. Packages are installed and managed in the operating
 system by a package manager.

courses/level101/linux_basics/linux_server_administration.md

@@ -22,7 +22,7 @@ An operating system is considered as multi-user if it allows multiple people/use
 
 As a server administrator, we are mostly concerned with the Linux servers which are physically present at a very large distance from us. We can connect to these servers with the help of remote login methods like SSH.
 
-Since Linux supports multiple users, we need to have a method which can protect the users from each other. One user should not be able to access and modify files of other users
+Since Linux supports multiple users, we need to have a method which can protect the users from each other. One user should not be able to access and modify files of other users.
 
 
 ## User/Group Management
@@ -64,8 +64,8 @@ command.
 
 ![](images/linux/admin/image9.png)
 
-If you want to understand each filed discussed in the above outputs, you can go
-through below links:
+If you want to understand each field discussed in the above outputs, you can go
+through the below links:
 
 - [https://tldp.org/LDP/lame/LAME/linux-admin-made-easy/shadow-file-formats.html](https://tldp.org/LDP/lame/LAME/linux-admin-made-easy/shadow-file-formats.html)
 
@@ -199,7 +199,7 @@ need to be a part of the sudo group.
 **How to provide superpriveleges to other users ?**
 
 Let's first switch to the root user using su command. Do note that using
-the below command will need you to enter the password for the root user.
+the below command will require you to enter the password for the root user.
 
 ![](images/linux/admin/image44.png)
 
@@ -239,7 +239,7 @@ Let's now switch back to user "shivam" and try to access the
 ![](images/linux/admin/image56.png)
 
 We need to use sudo before running the command since it can only be
-accessed with the sudo privileges. We have already given sudo privileges
+accessed with sudo privileges. We have already given sudo privileges
 to user “shivam” by adding him to the group “wheel”.
 
 
@@ -251,7 +251,7 @@ users and everybody else. This is to make sure that one user is not
 allowed to access the files and resources of another user.
 
 To see the permissions of a file, we can use the ls command. Let's look
-at the permissions of /etc/passwd file.
+at the permissions of the /etc/passwd file.
 
 ![](images/linux/admin/image40.png)
 
@@ -288,13 +288,13 @@ We will now create a new file and check the permission of the file.
 ![](images/linux/admin/image15.png)
 
 The group owner doesn't have the permission to write to this file. Let's
-give the group owner or root the permission to write to it using chmod
+give the group owner or root permission to write to it using chmod
 command.
 
 ![](images/linux/admin/image26.png)
 
 Chmod command can be also used to change the permissions of a directory
-in the similar way.
+in a similar way.
 
 ### Chown command
 
@@ -343,16 +343,16 @@ This method is also useful when we want some scripts to perform
 ssh-related tasks.
 
 Passwordless authentication requires the use of a public and private key pair. As the name implies, the public key can be shared with anyone but the private key should be kept private.
-Lets not get  into the details of how this authentication works. You can read more about it
-[here](https://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process)
+Let's not get into the details of how this authentication works. You can read more about it
+[here](https://www.digitalocean.com/community/tutorials/understanding-the-ssh-encryption-and-connection-process).
 
 Steps for setting up a passwordless authentication with a remote host:
 
-1. Generating public-private key pair  
+1. Generating a public-private key pair  
 
     **If we already have a key pair stored in \~/.ssh directory, we will not need to generate keys again.**
 
-    Install openssh package which contains all the commands related to ssh.
+    Install the openssh package which contains all the commands related to ssh.
 
     ![](images/linux/admin/image49.png)
 
@@ -437,12 +437,12 @@ Linux distributions.
 
 ![](images/linux/admin/image20.png)
 
-We did find an exact match for the keyword httpd when we searched using
+We did find an exact match for the keyword httpd when we searched using the
 yum search command. Let's now install the httpd package.
 
 ![](images/linux/admin/image28.png)
 
-After httpd is installed, we will use the yum remove command to remove
+After httpd is installed, we will use the yum remove command to remove the
 httpd package.
 
 ![](images/linux/admin/image43.png)
@@ -520,7 +520,7 @@ additional information about io and cpu usage.
 
 ## Checking Disk Space
 
-In this section, we will study about some useful commands that can be
+In this section, we will study some useful commands that can be
 used to view disk space on Linux.
 
 ### df (disk free)
@@ -580,7 +580,7 @@ used to start/stop/restart the services managed by systemd.
 ## Logs 
 
 In this section, we will talk about some important files and directories
-which can be very useful for viewing system logs and applications logs
+which can be very useful for viewing system logs and application logs
 in Linux. These logs can be very useful when you are troubleshooting on
 the system.