Triming strings and char - string

Question

I'm working on mini program. I have a List of Strings. I'm reading strings from .txt file, and if i have a word that contains 4 and more char then read it. Ok, that's i what is working. Then i need to write all strings (words) in another file, and it's working, but i have problem.
For example i have a word School (6char) and i need trim some char from words. For example
School = chool, hool, etc..
Program = rogram, ogram, gram, etc...
I need to get something like this, here's the code. My code is only working for first char, but not for other in the loop.
For example i will get Program = rogram, but not ogram, gram, etc...
My question is, how to get all trim words from my list of words in input .txt file i have for example:
Program,
school,
etc
and in output .txt file i need to get something like this:
rogram,
ogram,
gram,
chool,
hool,
Here's the code.
Dim path As String = "input_words.txt"
Dim write As String = "trim_words.txt"
Dim lines As New List(Of String)
'reading file'
Using sr As StreamReader = New StreamReader(path)
Do While sr.Peek() >= 4
lines.Add(sr.ReadLine())
Loop
End Using
'writing file'
Using sw As StreamWriter = New StreamWriter(write)
For Each line As String In lines
sw.WriteLine(line.Substring(1, 5))
Next
End Using

Answer 1

The While Loop
A simple way to approach the problem is to use a While loop while the length is bigger than 4
Here while our current string is more than 4 length:
We write it
We remove the first character
For Each line As String In lines
Dim current As String = line
While current.Length > 4
Console.Write(current & ",")
current = current.Remove(0, 1)
End While
Console.Write(current & vbNewLine)
Next
The For Loop
The second way to approach this is using a For loop where the idea is from the length of the current word to (5) applying a last -1 :
We write it
We remove the first character
For Each line As String In lines
Dim current As String = line
For i As Integer = line.Length To 5 Step -1
Console.Write(current & ",")
current = current.Remove(0, 1)
Next
Console.Write(current & vbNewLine)
Next

Answer 2

I made a different solution. Because i needed to limited to 4 char i made this.
Dim path As String = "input_words.txt"
Dim write As String = "trim_words.txt"
Dim lines As New List(Of String)
'reading file'
Using sr As StreamReader = New StreamReader(path)
Do While sr.Peek() >= 4
lines.Add(sr.ReadLine())
Loop
End Using
'writing file'
Using sw As StreamWriter = New StreamWriter(write)
For Each line As String In lines
Dim iStringLength = line.Length
Dim iPossibleStrings = iStringLength - 5
For i = 0 To iPossibleStrings
Console.WriteLine(line.Substring(i, 4))
Next
Next
End Using
Tnx for help #Mederic!