echo and read commands in UNIX

 [oracle]$ echo "Hello World"
Hello World
[oracle]$ read
Hi
[oracle]$ echo "Hello";echo "World"
Hello
World
[oracle]$ echo "what is your name?";read name;echo "Hello $name"
what is your name?
Raj
Hello Raj
[oracle]$ echo "what is your name?";read name;echo "Hello $name";echo "Press Enter to continue";read
what is your name?
Raj
Hello Raj
Press Enter to continue
[oracle]$

$ echo "One"
One
$ echo "one" > output.txt
$ cat output.txt
one
$ echo "one" > output.txt
$ cat output.txt
one
$ echo "one" >> output.txt
$ cat output.txt
one
one
$ echo "one" >> output.txt
$ cat output.txt
one
one
one
$