UNIX MCQ Questions for Exam and Interview Preparation | Computer Science

In Unix, the ls command is used to list directory contents. By using the -l option, it displays detailed information about the files and directories. Adding the -d option makes ls display the attributes of the directory itself rather than its contents.
So, ls -l -d is the correct command to display the directory attributes rather than its contents.

In Unix, the command cat ch will display the contents of all files in the current directory that have "ch" in their filenames. Therefore, it will display the contents of files like patch, catch, and .ch.
So, All of the above files will be displayed by the command cat ch.

In Unix, file permissions are represented by three digits in octal form. Each digit corresponds to a set of permissions: the first digit for the owner, the second for the group, and the third for others. The permissions are represented by adding up the values for read (4), write (2), and execute (1).

For the owner to have read, write, and execute permissions (7 = 4 + 2 + 1).
For the group and others to have read and execute permissions (5 = 4 + 1).

So, the octal number to be given along with the chmod command to achieve these permissions is 755.

In Unix, the stty command is used to change or display terminal settings. The intr option is used to specify the interrupt key, which is used to interrupt or terminate the current process. By default, the interrupt key is set to ^c, which represents Control-c. So, to use Control-c as the interrupt key, you would use the command stty intr ^c.
Therefore, Option B: stty intr ^c is the correct command to set Control-c as the interrupt key.

In Unix, grep is not a communication command. It is a powerful utility used for searching patterns in files. It stands for "global regular expression print".
On the other hand, the other options are indeed communication commands:

write: Used to send messages to another user logged in on the same system.
mesg: Used to control whether other users can send messages to you.
mail: Used to send and receive email messages.

So, Option D: grep is not a communication command.

In Unix, to move the cursor to the end of the paragraph, the key used is G (capital G) in vi or Vim.
Therefore, None of the above options correspond to the key used to move the cursor to the end of the paragraph.

In Unix, the command cat emp[!0-9] is used to concatenate all files beginning with the string 'emp' and followed by a non-numeric character. Here, the square brackets denote character classes, and the exclamation mark (!) negates the character class. So, [!0-9] matches any character that is not a numeric character.
Therefore, Option A: cat emp[!0-9] is the correct command to concatenate all files beginning with the string 'emp' and followed by a non-numeric character.

In Unix, the tee command reads the standard input and writes it to both the standard output and one or more files, effectively making a copy of the input. This can be useful when you want to see the output of a command on the screen while also saving it to a file.
So, tee is the correct command to transcribe the standard input to the standard output and also make a copy of the same in a file.

In Unix, the rm command is used to remove or delete files and directories. It stands for "remove".
So, rm is the correct command to remove a file.

In Unix, the semicolon (;) symbol is used to separate more than one command in the same command line. This allows you to execute multiple commands sequentially on a single command line.
So, ; is the symbol used to separate more than one command in the same command line.