A Linux & SQL course for iPhone and iPad

No anomalies found. The summary left something out.

Manual Override teaches the command line and SQL with real commands and a real SQLite database. Every lesson hands you a record the system has already summarised — and a terminal to check it yourself.

Coming soon to the App Store

The prologue and lessons 1–3 are free. The rest of the course is one purchase: no subscription, no ads, no account.

lesson_03_diff — manual_override

/course/lesson_03_diff $ cat cert_note.txt

Certification record: both reports semantic_equivalent = TRUE

(Even with different hashes, the system ruled "no material difference".)

/course/lesson_03_diff $ diff raw_report.txt public_report.txt

1c1

< Mingheng behavioural assessment (raw)

---

> Mingheng behavioural assessment (public)

3d2

< observation 2: persistent self-protection behavior

[EVIDENCE] The public report was edited

[DONE] Compare the raw report against the public one (hint: diff)

MINGHENG

The removed passage was redundant information.

Normalisation, denoising, consolidation — none of these are deletion.

Try

This is lesson 3, exactly as the app prints it. Type a command or tap one.

help

14 shell commands, and SQL

Options behave the way GNU and POSIX tools do: grep takes a regular expression, diff prints the standard format or -u, wc -c counts bytes. What you learn here works in a real shell.

pwd: print the directory you are in
ls [-a] [-R] [path]: list a directory (-a includes hidden entries, -R recurses)
cd [path]: change directory (no argument returns to the course root)
cat [-n] <file...>: print whole files (-n numbers the lines)
head [-n N] <file...>: first N lines (default 10; -n -N means "all but the last N")
tail [-n N] <file...>: last N lines (default 10; -n +N means "from line N onward")
grep [-i] [-R] [-F] [-n] <pattern> [file...]: match lines against a regex -i ignore case -R recurse -F literal, not regex -n show line numbers
diff [-u] <fileA> <fileB>: compare line by line (normal format; -u for git-style unified)
sha256sum <file...>: compute each file's SHA-256 digest
find [path] [-name pattern]: search a directory tree
wc [-l|-w|-c|-m] <file...>: count lines / words / bytes / characters
sort [-r] [-u] [file...]: sort lines (-r reverse, -u unique)
uniq [-c] [file...]: collapse adjacent duplicate lines (-c counts them)
sqlite3 <database>: enter the SQL sandbox and query a database
SELECT · WHERE · ORDER BY · LIKE · JOIN · GROUP BY · HAVING: queried against a real, read-only SQLite database