Run grep denied /var/log/auth.log | nl | head -n 3.
grep denied /var/log/auth.log | nl | head -n 3
Mission 326
Text evidence bridge
Checkpoint numbered logs, sorted comparisons, and bounded pipelines.
Text and logsgrepnlcommwc
Lesson 326 of 360
0/360 lessons
0/17 missions
Text and logs · 8 minutes
New learnerrank
0XP
0%complete
learner@clairos:/home/learner $
Unix ops lab: type a command, press Enter
Instructions
8 minutes
Click any instruction for the command details, the why, and the common mistake to avoid.
Run comm data/users-a.txt data/users-b.txt.
comm data/users-a.txt data/users-b.txt
Run wc -l /var/log/auth.log.
wc -l /var/log/auth.log
Save progress
Keep learning across sessions.
Create a free account to sync completed lessons, XP, streaks, course status, and your next lesson across sessions.
Checking account status...
Progress sync is idle.
0XP
New learnerrank
0day streak
0best streak
0daily streak
0lessons
0courses
0missions
0tasks
Noverified
Progress sync stores completion IDs, scores, streaks, badges, and game settings. Terminal contents, editor snippets, lab scratch, email, and real names are never published on leaderboards or share cards.
Lesson support
What to notice while you play.
Build repeatable confidence with combining text tools into defensible evidence.
Start with grep denied /var/log/auth.log | nl | head -n 3, inspect the result, then continue in order.
Combining text tools into defensible evidence helps operators explain what they know before they change anything.
- Skipping the output that proves combining text tools into defensible evidence.
- Changing several things before recording a baseline.
Reference
Commands in this lesson.
grep [-i] <text> <file>
Find literal text inside a file.
wc [-l] <file>
Count lines, words, and characters.
nl [file]
Number lines from a file or supported text pipeline.
comm <left> <right>
Compare two sorted text files line by line.