Introduction To Solaris - Lesson 1

Explanation
The UNIX derivatives used in Equifax are Linux, Solaris, and AIX. These operating systems are commonly used in enterprise environments and offer robust features and security. Linux is an open-source operating system that is highly customizable and widely used in server environments. Solaris is a UNIX-based operating system developed by Oracle, known for its scalability and reliability. AIX is IBM's UNIX-based operating system, designed for high-performance computing. These three operating systems are likely chosen by Equifax for their stability, security, and compatibility with their infrastructure.

Explanation
The guiding principles of UNIX development include making use of available tools or creating new ones when necessary, creating small simple programs that excel at one specific task, and expecting the output of one program to serve as the input for another program that is not yet known. These principles emphasize the flexibility, simplicity, and interoperability of UNIX systems.

Explanation
The "chmod" command allows you to change the permissions of a file. This command is used in Unix-like operating systems to modify the access permissions for files and directories. By using the chmod command, you can specify who can read, write, or execute a file.

Explanation
When the shell evaluates a command, programs found in your PATH variable do not take priority over aliases defined in your bashrc. Aliases defined in your bashrc take precedence over programs found in your PATH variable.

Explanation
A standardized system calls interface provides the benefit of making programs more portable between UNIX systems. This means that the programs can be easily transferred and run on different UNIX systems without requiring significant modifications or adaptations. This increases the flexibility and compatibility of the programs, allowing them to be used across various UNIX platforms without any major issues or complications.

Explanation
The popular derivatives of UNIX are Solaris, Linux, and Android. These operating systems are all based on the UNIX architecture and have gained popularity for their stability, security, and flexibility. Solaris is a UNIX-based operating system developed by Sun Microsystems, known for its scalability and reliability. Linux is a free and open-source operating system that has gained widespread adoption due to its versatility and community-driven development. Android, developed by Google, is a mobile operating system based on the Linux kernel, widely used in smartphones and tablets. Windows and OS/2 are not derivatives of UNIX, making them incorrect options.

Explanation
In every UNIX system, there are several standard directories that serve different purposes. The root directory ("/") is the top-level directory that contains all other directories and files. The "/usr" directory is used for storing user-related data, including user programs, libraries, and documentation. The "/dev" directory contains device files that represent hardware devices connected to the system. The "/bin" directory holds essential binary executables that are required for basic system functioning. Therefore, all of the given options ("/", "/usr", "/dev", and "/bin") are standard directories in every UNIX system.

Explanation
The statement "Only data files and programs are stored on a UNIX filesystem" is false. In addition to data files and programs, a UNIX filesystem can also store directories, symbolic links, device files, and special files. Directories are used to organize and structure the files and directories within the filesystem. Symbolic links are files that act as pointers to other files or directories. Device files represent hardware devices such as printers or disk drives. Special files are used for system operations and communication. Therefore, a UNIX filesystem can store a variety of file types, not just data files and programs.

Explanation
The three kinds of file access in UNIX file permissions are read, write, and execute. "Read" allows the user to view the contents of the file, "write" allows the user to modify the contents of the file, and "execute" allows the user to run the file as a program or script. These permissions are essential for controlling access to files and ensuring the security and integrity of the system.

Explanation
The two ways of setting file permissions in UNIX are relative and absolute. Relative permissions are set using symbols like +, -, or = to add, remove, or set permissions respectively. Absolute permissions are set using numerical values like 0-7, where each digit represents the permission for owner, group, and others respectively.

Explanation
The correct answer is .bash_profile and .bashrc. These two files are responsible for configuring the bash shell environment when a user logs in. The .bash_profile file is executed for login shells and sets up the user's personal environment variables and startup programs. The .bashrc file is executed for interactive non-login shells and contains settings and aliases specific to the user's preferences. By configuring these files, users can customize their bash shell environment according to their needs and preferences.

Explanation
All of the listed environment variables (PATH, TERM, PWD, HOME) are useful in different ways.

- PATH is an environment variable that specifies the directories where executable programs are located. It allows the operating system to find and execute programs without needing to specify their full path.
- TERM is an environment variable that specifies the type of terminal or terminal emulator being used. It helps in determining how text and other data should be displayed.
- PWD is an environment variable that stores the current working directory. It is useful for navigating and referencing files and directories.
- HOME is an environment variable that stores the path to the current user's home directory. It is often used by programs to locate user-specific configuration files and data.

Explanation
Ctrl+R is the correct keyboard shortcut to search through your bash command history buffer. This shortcut allows you to search for a previously entered command by typing a keyword or phrase and then pressing Ctrl+R. It will search backwards through your command history and display the most recent command that matches the search criteria. This is a useful shortcut for quickly finding and reusing commands without having to scroll through your entire command history.