UNIX MCQ Questions for Exam and Interview Preparation | Computer Science

In Unix, the vi command is a text editor that is commonly used to display and create files. It allows users to view and edit text files directly within the terminal. When you open a file with vi that doesn't exist, it creates a new file with that name.
So, vi is the command used to both display and create files in Unix.

In Unix file permissions, the three sets of permissions (rwx) represent the access rights for the owner, group, and others, respectively. The second set of permissions, indicated by (r-), means that the group associated with the file or directory has read permission only. The absence of the "w" (write) and "x" (execute) permissions indicates that the group does not have those permissions.
So, Option B is the correct interpretation of the second set of permissions (r-) in Unix file permissions.

When you issue the ls -l command in Unix, the output displays detailed information about files and directories in the current directory. The first column in the output represents the permissions of the file or directory. This column provides information about read, write, and execute permissions for the owner, group, and others, respectively.
So, Option D is the column that contains all details of the permissions of a file when you issue the ls -l command.

In Unix, the pwd command stands for "print working directory". When you issue this command, it displays the full pathname of the current working directory. This helps users to know which directory they are currently working in within the Unix filesystem.
So, Option C is the command used to display your working directory in Unix.

In Unix, when using the mail command to read or compose emails, the w command is used to save the mail in a separate file. After composing or reading an email, if you want to save it to a file, you can use the w command followed by the filename. This command writes the email content to the specified file.
So, Option C is the command used to save mail in a separate file while working with the mail command in Unix.

In Unix, the cmp command is used to compare two files byte by byte and determine whether their contents are identical or not. When you execute this command followed by the names of two files, it compares the files and provides information about the first byte where they differ, if any.
So, Option B is the command used to compare files in Unix.

In Unix, the kill command is used to terminate or send signals to processes. By default, it sends the TERM signal to a process, which instructs it to gracefully terminate. However, you can specify different signals using various options of the kill command. For instance, using kill -9 sends the KILL signal, which immediately terminates the process without allowing it to clean up.
So, Option D is the command used to terminate a process in Unix.

In the Unix sort command, the -k option is used to specify the key fields to be used for sorting. It allows you to define a custom sort field based on column position. The syntax for using this option is -k start[,end], where start and end are the positions of the starting and ending columns of the key field, respectively. The +m.n option specifies sorting starting after the nth column of the mth field.
Therefore, Option B is the correct choice.

The cp command in Unix is used to copy files and directories from a source to a destination. It does not involve standard input or standard output files. Instead, it directly works with file system paths as source and destination arguments.
Therefore, Option D is the correct choice.

In Unix-like operating systems, including Linux, the /etc/shadow file stores encrypted password and other security-related information such as password aging policies for user accounts. It is readable only by the root user and provides enhanced security compared to the older /etc/passwd file.
Therefore, Option A is the correct choice.