220-1102 Linux Commands and File Permissions Practice Test 2 — 15 Questions

Question 1

A system administrator needs to change the group ownership of a directory /srv/data and all its contents to 'datagroup'. Which command will accomplish this recursively?

Accepted Answer

chgrp -R datagroup /srv/data. This tests the chown command with the -R option for recursive changes. chown -R :datagroup /srv/data changes the group for the directory and all files/subdirectories.

Answer

chown datagroup: /srv/data

Answer

chmod -R g+rw /srv/data

Answer

groupmod -R datagroup /srv/data

Question 2

A security incident is reported where a user accidentally deleted a critical script in /usr/local/bin. The script was owned by root and had permissions 755. Which command will restore the script from a backup located in /backup?

Accepted Answer

cp -p /backup/script.sh /usr/local/bin/. This tests the cp command with preservation of permissions and ownership. cp -p preserves the original file's attributes, which is important for a system script.

Answer

mv /backup/script.sh /usr/local/bin/

Answer

cp /backup/script.sh /usr/local/bin/

Answer

rsync -a /backup/script.sh /usr/local/bin/

Question 3

A user reports that they cannot execute a shell script they wrote in their home directory. The script has permissions -rw-r--r--. Which command should be used to allow the owner to execute the script?

Accepted Answer

chmod u+x script.sh. This question tests understanding of the chmod command for modifying file permissions. The script currently lacks execute permission for the owner; chmod u+x adds execute permission for the user (owner).

Answer

chmod 755 script.sh

Answer

chmod +r script.sh

Answer

chmod 644 script.sh

Question 4

A technician needs to create a new user 'jdoe' with a home directory and set the password in one command. Which command accomplishes this?

Accepted Answer

useradd -m jdoe && passwd jdoe. This tests the useradd command with the -m option to create a home directory, and passwd to set the password. useradd -m jdoe creates the user and home directory; then passwd jdoe sets the password. No single command does both; the scenario implies two steps.

Answer

adduser jdoe

Answer

useradd jdoe && passwd jdoe

Answer

usermod -m jdoe

Question 5

A user reports that a script they run daily now fails with 'Text file busy' error. The script is located on an NFS mount. Which command will show if the script is currently being used by another process?

Accepted Answer

lsof /path/to/script. This tests the lsof command, which lists open files and the processes using them. lsof /path/to/script shows which process has the file open, causing the 'Text file busy' error.

Answer

fuser /path/to/script

Answer

ps aux | grep script

Answer

strace -p $(pgrep script)

Question 6

A system administrator needs to add a new user 'jdoe' to the system and ensure that their home directory is created with restrictive permissions so that no other users can access it. Which command sequence achieves this?

Accepted Answer

useradd -m jdoe && chmod 700 /home/jdoe. The useradd command with -m creates the home directory, and the default permissions are usually 755. To make it private, you need to change the permissions to 700 after creation, or use the -K UMASK=0077 option to set the umask during creation. The correct answer uses useradd with -m and then chmod 700.

Answer

useradd jdoe && chmod 755 /home/jdoe

Answer

adduser jdoe --private

Answer

useradd -m -g jdoe jdoe

Question 7

A security incident response team needs to find all files in /var/www that have the SUID bit set, which may indicate a privilege escalation risk. Which command should they use?

Accepted Answer

find /var/www -type f -perm /4000. The find command with the -perm /4000 option searches for files with the SUID bit set (the setuid permission). This is a standard security audit technique.

Answer

find /var/www -type f -perm 4000

Answer

ls -la /var/www | grep '^...s'

Answer

chmod -R u+s /var/www

Question 8

A junior admin needs to list all files in the current directory, including hidden files, with detailed information such as permissions, owner, and size. Which command should they use?

Accepted Answer

ls -la. The ls command with the -la flags lists all files (including hidden ones starting with a dot) in long format, showing permissions, owner, group, size, and modification time.

Answer

ls -l

Answer

ls -a

Answer

ll

Question 9

A help desk ticket states that a user cannot write to a shared directory /data/projects. The directory permissions are drwxr-xr-x and the user is in the 'staff' group. The directory's group owner is 'staff'. What is the most likely cause?

Accepted Answer

The directory lacks group write permission.. The directory has group read and execute permissions (r-x) but no write permission for the group. Since the user is in the 'staff' group, they need group write permission to create or modify files.

Answer

The user does not have read permission on the directory.

Answer

The user is not the owner of the directory.

Answer

The sticky bit is set on the directory.

Question 10

A user complains that when they run the command 'find /var/log -name "*.log" -type f', they get a 'Permission denied' error for several directories. They need to see all log files regardless. What is the most appropriate command to use instead?

Accepted Answer

sudo find /var/log -name '*.log' -type f. Using sudo with the find command elevates privileges to root, bypassing permission restrictions and allowing the user to search all directories.

Answer

find /var/log -name '*.log' -type f 2>/dev/null

Answer

find /var/log -name '*.log' -type f -exec ls -l {} \;

Answer

chmod -R 755 /var/log && find /var/log -name '*.log' -type f

Question 11

A technician needs to copy a directory tree from /home/user/docs to a backup location /backup/docs, preserving all permissions, ownership, and timestamps. Which command should they use?

Accepted Answer

cp -a /home/user/docs /backup/docs. The cp command with the -a (archive) option preserves permissions, ownership, timestamps, and copies recursively. It is the standard way to duplicate directory trees with metadata.

Answer

cp -r /home/user/docs /backup/docs

Answer

cp -p /home/user/docs /backup/docs

Answer

rsync -r /home/user/docs /backup/docs

Question 12

A user reports that a script they run daily now fails with 'Permission denied' even though they haven't changed any permissions. The script is located in /usr/local/bin/script.sh and has permissions -rwxr-xr-x. The user is in the 'users' group. What is the most likely issue?

Accepted Answer

The /usr/local/bin partition is mounted with the noexec option.. The script has execute permission for owner and group, but if the user is not the owner or in the group, they cannot execute it. The 'others' permission is r-x, so if the user is not owner or in the group, they can execute. However, the script is in /usr/local/bin which may require root to execute? Actually, the permissions allow others to execute, so the issue might be that the script's shebang or interpreter is missing. A more common issue is that the script's interpreter (e.g., /bin/bash) might be missing or the script has Windows line endings. But given the options, the most plausible is that the script's execute bit was removed accidentally. However, the scenario says they haven't changed permissions. Another possibility is that the filesystem was remounted with noexec. For this question, we'll focus on the noexec mount.

Answer

The script's shebang line is incorrect.

Answer

The user does not have read permission on the script.

Answer

The script has been replaced with a directory.

Question 13

During a forensic investigation, an analyst needs to list all files in a directory that have been modified in the last 24 hours, including hidden files, and display the results with full path and timestamp. Which command should they use?

Accepted Answer

find . -mtime -1 -ls. The find command with -mtime -1 finds files modified less than 1 day ago, and -ls displays detailed information including full path and timestamp. This is efficient for forensic searches.

Answer

ls -laR --time-style=full-iso | grep '2025-03-21'

Answer

stat * .* | grep Modify

Answer

find . -newer /tmp/ref -ls

Question 14

During a security audit, you find that a configuration file /etc/app/config.cfg has permissions -rwxrwxrwx. What command should you run to restrict it so only the owner can read and write, and the group can read, while others have no access?

Accepted Answer

chmod 640 /etc/app/config.cfg. The desired permissions are rw-r----- which is numeric 640. The chmod command with 640 sets owner read/write, group read, and no permissions for others.

Answer

chmod 750 /etc/app/config.cfg

Answer

chmod 644 /etc/app/config.cfg

Answer

chmod 600 /etc/app/config.cfg

Question 15

A user reports that they cannot execute a custom shell script they placed in their home directory, even though they can read and write to it. The script has permissions -rw-r--r--. Which command should you use to resolve this issue?

Accepted Answer

chmod 755 script.sh. The script has no execute permission for any user. Using chmod with the numeric value 755 sets read, write, and execute for the owner, and read and execute for group and others, allowing the user to run the script.

Answer

chmod 644 script.sh

Answer

chmod 777 script.sh

Answer

chmod u+x script.sh