A system call is a service provided by the Linux kernel. The functions which change the execution mode of the program from user mode to kernel mode are known as system calls. These calls are required in case some services are required by the program from the kernel. For example, if we want to change…
The debugger is the program that you use to figure out why your program isn’t behaving the way you think it should. The purpose of a debugger is to allow you to see what is going on inside your program while it runs. A debugger can be a handy tool. Many programmers use basic intuition…
Linux operating system provides an outstanding environment for programming with its rich set of language and development tools. C is one of the most popular system programming languages to use in conjunction with Linux, in part because the operating system itself is written mostly in C. Using these languages, programmers can easily access system services…
In this post, we are going to see the commands for the vi editor. Word and Character Searching The vi editor has two kinds of searches: string and character. For a string search, the/and? commands are used. When we start these commands, the command just typed will be shown on the bottom line, where we…
The vi editor is available on almost all Linux and Unix systems. vi can be used from any type of terminal because it does not require the cursor-moving keys and function keys the alphabetic keys can be used for commands. vi (often pronounced vee – eve) is short for visual editor. It is a visual…
Environment and Path Setting in Linux – Bash shell is used for various purposes under Linux. How do you customize the shell environment variable under Linux operating systems? You can use shell variables to store data, set configuration options, and customize the shell environment under Linux. The default shell is Bash under Linux and can…
Unix files consist of two parts: the data part and the filename part. The data part is called an ‘inode’. The inode carries the map of, where the data and the file permissions for the data exist. More than one filename can reference the same inode number; these files are said to be hard linked’….
Changing File Access Permissions – The Linux file access permission scheme lets you give other users access to the files you want to share yet keep your private files confidential. You can allow other users to read from and write to a file (handy if you are one of several people working on a joint…
Every File or directory in Linux has access permissions. There are three types of permissions Permissions are defined for three types of users: Thus, Linux access permissions are nine bits of information (3 types x 3 types of users), and each of them may have just one of two values: allowed or denied File Permission…
File System – Linux has a hierarchical filesystem (directories within directories and files, and directories, and device drivers are treated as files). Filesystem supports 256 – character filenames avoid symbols and punctuation except for the dot (.). All command line entries are case-sensitive. Also, note that Linux uses the slash (/) rather than the backslash…
chmod command Changing access permission for files and directories. chmod changes the permissions of the given file according to mode, which can be either a symbolic representation of changes to make or an octal number representing the b pattern for the new permissions. It manages the mode of the file. chmod has two modes: Symbolic…
Info Pages or info Command – While man pages are great sources of information about a command or concept, the fact that it provides one long page means that longer documents are hard to read. The info format was developed as a way to store more comprehensive instructions on your system. If a particular command…
