EX200 Essential Tools Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  tail -n 15 /var/log/messages

  Why this is correct

  tail -n 15 /var/log/messages is correct because tail reads from the end of a file, and the -n 15 flag limits output to exactly the last 15 lines. Unless told otherwise, tail prints the final 10 lines; -n overrides this default to match the requested count. The command then exits, providing a clean, one-time snapshot of the most recent entries in the system log.

• ✗

  tail -f /var/log/messages

  Why it's wrong here

  tail -f /var/log/messages does not simply show the last 15 lines; the -f (follow) flag makes tail output the last 10 lines by default and then remain attached to the file, continuously printing every new line that is appended. This means the command never terminates on its own, making it useless for a one-off requirement of viewing exactly 15 lines, and it floods the terminal with ongoing updates instead.

• ✗

  cat /var/log/messages

  Why it's wrong here

  cat /var/log/messages prints the entire contents of the file from the very first line to the last, which for a long-running system log can be thousands of lines or more. It does not apply any line-count limit, so it far exceeds the requested 15 lines and could overwhelm the terminal or scroll those last lines off the screen entirely.

• ✗

  head -15 /var/log/messages

  Why it's wrong here

  head -15 /var/log/messages displays the first 15 lines of the log file, which correspond to the oldest records in the file, not the newest. This is the functional opposite of what the user wants; the last lines of a log are typically the most relevant for troubleshooting, and head provides no option to count from the end.

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