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Many times there can be un-intentional delete of files or directories. That can lead to loss of important data or some misconfiguration of the system so we need a way to stop the accidental deletion of files and directories it may not be applicable to all the files and directories but we can have a design where at least some files and directories are prevented from such scenario.We use the change attribute command to prevent scenario below will see how this command is applied to two files and directories.SyntaxBelow is the syntax of change attribute command.chattr [operator] [flag] [filename] Where ... Read More
Binary search tree (BST) is a special type of tree which follows the following rules −left child node’s value is always less than the parent Noteright child node has a greater value than the parent node.all the nodes individually form a binary search tree.Example of a binary search tree (BST) −A binary search tree is created in order to reduce the complexity of operations like search, find minimum and maximum.Delete Operation binary search tree (BST)delete operation is dropping the specified node from the tree. in case deleting the nodes, there are three possibilities −Deleting a leaf node from the tree: ... Read More
The file systems in Linux can be of different types. They support different file sizes and some mechanism like journaling etc. Also different types of file systems are supported by different Linux Kernel systems. So for the devices which are available as memory in the Linux System, we can determine their file types by using the following commands.Using lsblkThis command dispalys all the attached divices as well as their file types and partitions.$ lsblk -fRunning the above code gives us the following result −NAME FSTYPE LABEL UUID MOUNTPOINT sr0 sda ├─sda2 ├─sda5 swap 02a54ace-c5c2-41cf-a679-acd9b460ee79 [SWAP] └─sda1 ext4 ae7c051f-451b-45ad-80a3-347c70a9de5e /Using fileIt ... Read More
Adding a single new user to a Linux system can be achieved through the useradd command. But system admins often get request to add many users. So Linux provides a different to do a bulk addition of many users to a system.This is the newusers command.Synatxsudo newusers user_deatils.txt user_details.txt is the file containing the details of all the usernames to be added.User DetailsBelow we see the structure of user_details.txt file.UserName:Password:UID:GID:comments:HomeDirectory:UserShell So we create a file with below details to add many usres.~$ cat MoreUsers.txt uname1:pwd#@1:2112:3421:storefront:/home/uname1:/bin/bash uname3:pwd#!@3:2112:3525:backend:/home/uname3:/bin/bash uname4:pwd#$$9:9002:4721:HR:/home/uname4:/bin/bashGiving Permissions to the User Details FileBefore we sue the user details file to ... Read More
Linux shell scripting has many powerful tools to process the data in files. One such feature is to find patterns and count the number of occurrences of matched patterns. One such example is to count the number of occurrences of a specific word in a given file. This is achieved by combination of commands for pattern search and counting. Below are the approaches which can be used for this need.Input fileLets use the below file for demonstrating the examples.$ cat inspire.txt Mastering anything needs practice. It also needs patience. And it needs time and other resources.Using grep and wcThe grep ... Read More
It often becomes essential to know not just the count of files in my current directory but also the count of files from all the subdirectories inside the current directory. This can be found out using theUsing lswe can use ls to list the files, then choose only the ones that start with ‘-‘ symbol. The R option along with the l option does a recursive search. The ‘-c’ option counts the number of lines which is the number of files.ls -lR . | egrep -c '^-'Running the above code gives us the following result −13Using find With Hidden FilesThe ... Read More
A binary search known as logarithmic search is a search algorithm that searches for an element in a sorted array. The algorithm recursively divides the array into two halves, if the element is found at the mid position then return otherwise call the divide and check again until the element is found.WorkingThe algorithm works by comparing the middle element of the sorted array with the element that is to be searched.If the search element is equal to the middle element, then return the index of the element.If the search element is greater than the middle element, search in the left ... Read More
Gogo is a tool to bookmark directories with long and complicated paths in the Unix shell. Because the long parts are difficult to remember and cumbersome to type in. In this article we'll see how to install go go and use it.Installing gitWe first need to have git installed in our system which will be needed for gogo installation. To install git in an Ubuntu system follow the below command.$ sudo apt install gitRunning the above code gives us the following result −[sudo] password for ubuntu: Reading package lists... Done Building dependency tree Reading state information... Done The following additional ... Read More
To use case-insensitive switch-case in JavaScript, make the input all upper or all lowercase.ExampleYou can try to run the following code to learn how to use a case-insensitive switch: JavaScript Strings var str = "amit"; str = str.toUpperCase(); switch (str) { case 'AMIT': document.write("The name is AMIT "); break; case 'JOHN': document.write("The name is JOHN "); break; default: document.write("Unknown name") } document.write("Exiting switch block");
A multiway tree is defined as a tree that can have more than two children. If a multiway tree can have maximum m children, then this tree is called as multiway tree of order m (or an m-way tree).As with the other trees that have been studied, the nodes in an m-way tree will be made up of m-1 key fields and pointers to children.multiway tree of order 5To make the processing of m-way trees easier some type of constraint or order will be imposed on the keys within each node, resulting in a multiway search tree of order m ... Read More