You want to check if the current user is root by comparing the user ID. Which command correctly tests this in a script?

hard📝 Application Q9 of 15

Linux CLI - Users and Groups

A[ "$(id -g)" -eq 0 ] && echo "Root user" || echo "Not root"

B[ "$(whoami)" -eq 0 ] && echo "Root user" || echo "Not root"

C[ "$(id -un)" = "root" ] && echo "Root user" || echo "Not root"

D[ "$(id -u)" -eq 0 ] && echo "Root user" || echo "Not root"

Step-by-Step Solution

Solution:

Step 1: Understand root user ID
Root user has user ID 0.
Step 2: Check command correctness
[ "$(id -u)" -eq 0 ] && echo "Root user" || echo "Not root" compares numeric user ID to 0 correctly. [ "$(id -un)" = "root" ] && echo "Root user" || echo "Not root" compares username string but uses wrong operator for numeric test.
Final Answer:
[ "$(id -u)" -eq 0 ] && echo "Root user" || echo "Not root" -> Option D
Quick Check:
Use numeric ID 0 to identify root [OK]

Quick Trick: Check id -u equals 0 to detect root user [OK]

Common Mistakes:

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