Sec. 12: Managing File Ownership and Permission

The command to change the ownership of a file in a text-mode manner is _______.

• chnguser

• chown

• transferown

Answer explanation

The chown command is used to change the ownership of a file.

The ls command:

• lists the files in a directory

• shows the current owner of a file

• lists all the users using a file

The permission string rwxrwxrwx means

• Read permission for the owner, no permission for anybody else.

• Read, write, and execute permissions for all users.

• Read and write permissions for the owner. Read-only permission for all others.

Answer explanation

The rwxrwxrwx is equivalent to 777. This allows for read, write, and execute permission for the user, the user’s group, and all other users on the system.

Which permission string will be represented by this type of permission: “Read and write permission for the user. The user's group and all other users should only be able to read the file.”

• rw-r—r—

• r––––––––

• rwxrwxrwx

Answer explanation

The rw-r--r-- is equivalent to 644. This allows for read and write permission for the user, and only read permissions for the user’s group and all other users on the system.

The sticky bit can be set with the chown command in either of two ways:

• Kernel and Daemon

• Octal Code and Symbolic Code

• Parse and Compile

Answer explanation

The sticky bit can be set using the octal code of the symbolic code.

Users can change anyone’s password on the system using the “sudo passwd username” command.

• True

• False

Answer explanation

The passwd command is used to change a user’s password. If you execute it as root (using sudo), then you can change anyone’s password on the system.

The SUID option tells Linux to run the program with the permissions of whoever owns the file rather than with the permissions of the user who runs the program.

• True

• False

Answer explanation

True, the SUID option tells Linux to run the program with the permissions of whoever owns the file rather than with the permissions of the user who runs the program.

What are two special permission bits exist, similar to the sticky bit?

• SUID and SGID

• UID and User

• Octal Code and Symbolic Code

Answer explanation

The SUID and SGID are special permission bits. SUID (Set owner User ID up on execution) is a special type of file permissions given to a file. Normally in Linux/Unix when a program runs, it inherits access permissions from the logged in user. SUID is defined as giving temporary permissions to a user to run a program/file with the permissions of the file owner rather that the user who runs it. SGID permission is similar to the SUID permission, the only difference is – when the script or command with SGID on is run, it runs as if it were a member of the same group in which the file is a member.

Linux has a dedicated filesystem feature to hide files from ls command.

• True

• False

Answer explanation

False, the Linux filesystem used the dot (.) character to hide files from the ls command, unless the “ls -la” command is used.

In order to hide a file or directory from being viewed by the ls command, you just have to:

• Put * in the beginning of the filename

• Put . in the beginning of the filename

• Save the file as a .xyz file

Answer explanation

The Linux filesystem used the dot (.) character to hide files from the ls command, unless the “ls -la” command is used.