Any program that is created to run in the UNIX/LINUX shell is known as a shell. LINUX has the Bourne shell, the C shell, the Korn shell, and the GNU Bourne-again shell. A shell can be defined as a command-line interpreter. Shell scripts manipulate files, execute programs and even print texts. They also consist of many constructs that determine what the shell environment does and at what time. We can say that a shell is a complete programming language because it has variables, control structures, etc. Moreover, regardless of how convoluted a script is, it is still a file of instructions that run in sequence.
AWK is a scripting language that analyzes data and creates reports. It is a type of command programming language that does not require any compiling. The programmer can use numeric functions, variables, logical operators, and string functions. AWK scripting involves writing small but effective codes that are in the form of statements. These codes are used to find patterns in a line of a document. When a matching pattern is found within a line, a specific action is taken. It is a type of scripting that uses processing and scanning.
Linux Implementation of Threads
In Linux, threads are implemented uniquely as standard processes. The Linux kernel has no concept of a thread. It doesn’t offer any special data structures or scheduling semantics for thread representation. Rather, the Linux kernel considers threads as mere processes that share specific computer resources with other tasks. Linux threads have a distinctive task_struct and may split services like address space with other tasks running concurrently. The method adopted by Linux is in contrast to other operating systems like Microsoft Windows that provides great kernel support for threads.
Disk Imaging and Cloning
Disk imaging involves creating an image of a partition or the entire hard drive. It is a process that comes in handy when you want to copy the drive for recovery or backup purposes. Linux offers four disk cloning solutions:
The dd or the disk destroyer is a powerful tool in Linux that can be used to partition or clone an entire hard disk drive.
Partrimage is a partition cloning tool that doesn’t have the risks of the disk destroyer like accidentally deleting the HDD with a typo.
Partclone is an advanced alternative to dd. It supports backing up the ext4 filesystem. While it is simple to use, the user must be familiar with text commands.
Clonezilla is a flexible imaging solution that is based on Partclone. It supports all file systems and is available as a bootable ISO.