VBScript AtEndOfLine Property

last modified April 9, 2025

The AtEndOfLine property in VBScript is part of the TextStream object. It indicates whether the file pointer has reached the end of a line in a text file. This property is read-only and returns True or False. It's essential for reading text files line by line or character by character.

AtEndOfLine helps control file reading operations precisely. It works with the TextStream object's methods like Read and ReadLine. This tutorial covers AtEndOfLine with practical examples to demonstrate its usage.

AtEndOfLine Property Overview

The AtEndOfLine property checks if the file pointer is at the end of a line. It returns True only when the pointer reaches a line terminator. The property is used with TextStream objects opened for reading.

Key features include detecting line endings during sequential file reading. It doesn't move the file pointer or modify the file. AtEndOfLine helps process text files with precise control. Understanding this property is crucial for text file manipulation.

Basic File Reading with AtEndOfLine

This example demonstrates the simplest use of AtEndOfLine to read a text file character by character. It shows how the property changes when encountering line endings. The script reads until the end of the first line.

basic_ateol.vbs

Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.OpenTextFile("test.txt", 1) ' 1 = ForReading

Do Until file.AtEndOfLine
    char = file.Read(1)
    WScript.Echo char
Loop

file.Close
Set fso = Nothing

The script opens "test.txt" for reading and reads one character at a time. The loop continues until AtEndOfLine becomes True. Each character is echoed to the output. This demonstrates basic end-of-line detection.

Processing Multiple Lines with AtEndOfLine

This example shows how to process an entire file using both AtEndOfLine and AtEndOfStream. It reads each line character by character while tracking line endings. The script handles multiple lines in a text file.

multiline_ateol.vbs

Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.OpenTextFile("data.txt", 1)

Do Until file.AtEndOfStream
    Do Until file.AtEndOfLine
        char = file.Read(1)
        WScript.Echo "Char: " & char
    Loop
    WScript.Echo "End of line reached"
    file.SkipLine ' Move to next line
Loop

file.Close
Set fso = Nothing

The outer loop checks for end of file, while the inner loop checks for end of line. Each character is processed individually. When a line ends, a message is displayed. SkipLine moves to the next line.

Counting Characters per Line

This example uses AtEndOfLine to count characters in each line of a file. It demonstrates practical file analysis using the property. The script tracks line numbers and their respective lengths.

count_chars.vbs

Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.OpenTextFile("document.txt", 1)
lineNum = 1

Do Until file.AtEndOfStream
    charCount = 0
    Do Until file.AtEndOfLine
        file.Read(1)
        charCount = charCount + 1
    Loop
    WScript.Echo "Line " & lineNum & ": " & charCount & " characters"
    lineNum = lineNum + 1
    file.SkipLine
Loop

file.Close
Set fso = Nothing

The script reads through each line without storing characters. It increments a counter for each character read. After each line, it reports the line number and character count. This shows how to use AtEndOfLine for analysis.

Custom Line Processing with AtEndOfLine

This example demonstrates custom line processing using AtEndOfLine. It reads lines but processes specific characters differently. The script converts vowels to uppercase while reading.

custom_processing.vbs

Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.OpenTextFile("input.txt", 1)
output = ""

Do Until file.AtEndOfStream
    Do Until file.AtEndOfLine
        char = file.Read(1)
        If InStr("aeiou", LCase(char)) > 0 Then
            output = output & UCase(char)
        Else
            output = output & char
        End If
    Loop
    output = output & vbCrLf ' Add line break
    file.SkipLine
Loop

WScript.Echo output
file.Close
Set fso = Nothing

The script reads each character and checks if it's a vowel. Vowels are converted to uppercase in the output. Other characters remain unchanged. AtEndOfLine controls the inner reading loop. The modified text is built in the output variable.

Reading Fixed-Width Fields with AtEndOfLine

This example shows how to read fixed-width fields using AtEndOfLine. It processes each line in segments of specific lengths. The script demonstrates structured file parsing.

fixed_width.vbs

Set fso = CreateObject("Scripting.FileSystemObject")
Set file = fso.OpenTextFile("records.txt", 1)

Do Until file.AtEndOfStream
    field1 = file.Read(10) ' First 10 chars
    field2 = file.Read(15) ' Next 15 chars
    field3 = file.Read(5)  ' Next 5 chars
    
    WScript.Echo "Field 1: " & Trim(field1)
    WScript.Echo "Field 2: " & Trim(field2)
    WScript.Echo "Field 3: " & Trim(field3)
    
    ' Skip remaining characters in line if any
    Do Until file.AtEndOfLine
        file.Read(1)
    Loop
    file.SkipLine
Loop

file.Close
Set fso = Nothing

The script reads specific character counts for each field. It uses AtEndOfLine to handle variable-length lines. Fields are trimmed to remove extra spaces. This approach is useful for fixed-format data files. The inner loop ensures proper line termination handling.

Source

TextStream Object Documentation

In this article, we have explored the AtEndOfLine property in VBScript, covering its usage and practical applications. From basic file reading to complex text processing, these examples demonstrate precise line handling. With this knowledge, you can enhance your file processing scripts with better control.

Author

My name is Jan Bodnar and I am a passionate programmer with many years of programming experience. I have been writing programming articles since 2007. So far, I have written over 1400 articles and 8 e-books. I have over eight years of experience in teaching programming.

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