Print a given line of a text file in bash

1. fos@ubuntu:~/dev/java$ head -n 4 HelloWorld.java  |tail -1
public class HelloWorld {

2. fos@ubuntu:~/dev/java$ sed -n '4p' HelloWorld.java

public class HelloWorld {

fos@ubuntu:~/dev/java$ sed  '4!d' HelloWorld.java

public class HelloWorld {

fos@ubuntu:~/dev/java$ sed '4q;d' HelloWorld.java    # efficient on large files

public class HelloWorld {

3. fos@ubuntu:~/dev/java$ ex +4p -scq HelloWorld.java

public class HelloWorld {

4. fos@ubuntu:~/dev/java$ awk 'FNR==4 {print $0}' HelloWorld.java

public class HelloWorld {

5. .....