Update 3_AdvancedTerminal.md

source/3_AdvancedTerminal.md

@@ -27,6 +27,7 @@ File2.txt:
 wget --no-check-certificate 'https://docs.google.com/uc?export=download&id=17kYqxphGrkCK30FQuOUDIXOUhiZvjAMd' -O file2.txt
 ```
 **1. file1.txt contains the text of a Sherlock Holmes book. How many lines of the file does it take to recount his tale in Bohemia?**
+*Hint: The table of contents is form line 48 to 70*
 <details>
   <summary>Stumped? Click me!</summary>
 
@@ -35,6 +36,10 @@ wget --no-check-certificate 'https://docs.google.com/uc?export=download&id=17kYq
   ```shell
   head -n 70 file1.txt | tail -n 22
   ```
+  You can also use command `awk` which is a great multipurpose effecitent text processing command.
+  ```shell
+  awk "NR<70" file1.txt | awk "NR>48"
+  ```
 </details>
 
 **2. How many lines in file2.txt contain a period? (*Hint: The answer is not 60*)**