course: fix P0 content errors + completion/mobile/keyboard UX (review A)

1 files changed, 16 insertions, 12 deletions

diff --git a/course/chapters/03-commands.json b/course/chapters/03-commands.json
index 10807cb..40fa2ad 100644
--- a/course/chapters/03-commands.json
+++ b/course/chapters/03-commands.json
@@ -7,16 +7,17 @@
     {
       "id": "3.1",
       "title": "Find any command fast",
-      "objective": "Use help, commands and check to discover what exists before guessing.",
+      "objective": "Use help, doctor and status to discover what exists before guessing.",
       "minutes": 7,
       "commands": [
         "help",
+        "doctor",
         "status"
       ],
       "blocks": [
         {
           "type": "text",
-          "text": "`help` groups all 344 commands by the module that owns them."
+          "text": "`help` groups every registered command by the module that owns them."
         },
         {
           "type": "cmd",
@@ -28,18 +29,20 @@
         },
         {
           "type": "tip",
-          "text": "`check` shows module requirements — the fastest way to explain a command that is listed but not working."
+          "text": "`doctor` shows module requirements — the fastest way to explain a command that is listed but not working."
         }
       ],
       "exercise": {
-        "instruction": "Open the help for `webdav-push`.",
+        "instruction": "Run `doctor` and read its severity ranking.",
         "accept": [
-          "help webdav-push"
+          "doctor",
+          "help",
+          "status"
         ],
         "check": {
           "type": "command"
         },
-        "hint": "Type: help webdav-push"
+        "hint": "Type: doctor"
       },
       "quiz": {
         "q": "Which command shows usage for one command?",
@@ -74,11 +77,11 @@
         },
         {
           "type": "cmd",
-          "text": "ls | grep txt"
+          "text": "grep hello hello.txt"
         },
         {
           "type": "warn",
-          "text": "`sed s/x/y/` substitutes the first match per LINE, not per file. `sed -i` is flagged destructive and needs confirmation."
+          "text": "`sed s/x/y/` substitutes the first match per LINE, not per file. `sed -i` overwrites the file immediately — checkpoint first (`checkpoint before-sed`). Pipes are partial in this build: `ls | grep x` may print the unfiltered listing; use `grep pattern file`."
         },
         {
           "type": "text",
@@ -90,15 +93,16 @@
         }
       ],
       "exercise": {
-        "instruction": "Search the current listing for `txt`.",
+        "instruction": "Search a file for a word (create `hello.txt` with `edit` if needed).",
         "accept": [
-          "ls | grep txt",
-          "grep txt"
+          "grep hello hello.txt",
+          "grep * hello.txt",
+          "grep hello *"
         ],
         "check": {
           "type": "command"
         },
-        "hint": "Type: ls | grep txt"
+        "hint": "Type: grep hello hello.txt"
       },
       "quiz": {
         "q": "`sed s/a/b/` replaces…",