[vbscript] Reading and Writing Text Files

Reading and Writing Text Files

https://technet.microsoft.com/en-us/library/ee198716.aspx

Creating Text Files

Listing 4.32 Creating a Text File

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.CreateTextFile("C:\FSO\ScriptLog.txt")

If the file does not exist, the CreateTextFile method creates it. If the file does exist, the CreateTextFile method will overwrite the existing file and replace it with the new, blank file. If you prefer that the existing file not be overwritten, you can include the optional Overwrite parameter. When this parameter is False, existing files are not overwritten; when this parameter is True (the default value), existing files are overwritten. For example, the following code sample does not overwrite the file C:\FSO\ScriptLog.txt if that file already exists:

Set objFile = objFSO.CreateTextFile("C:\FSO\ScriptLog.txt", False)

Listing 4.33 Creating a File Name

Set objFSO = CreateObject("Scripting.FileSystemObject")
For i = 1 to 10
 strTempFile = objFSO.GetTempName
 Wscript.Echo strTempFile
Next

rad646E9.tmp
radEC50C.tmp
rad0C40A.tmp
radE866E.tmp
rad77F3D.tmp
rad19970.tmp
rad7A21A.tmp
radB9DDC.tmp
rad84930.tmp 

rad92199.tmp

Listing 4.34 Creating and Naming a Text File

Set objFSO = CreateObject("Scripting.FileSystemObject")
strPath = "C:\FSO"
strFileName = objFSO.GetTempName
strFullName = objFSO.BuildPath(strPath, strFileName)
Set objFile = objFSO.CreateTextFile(strFullName) 

objFile.Close

• For reading (parameter value = 1, constant = ForReading). Files opened in this mode can only be read from. To write to the file, you must open it a second time by using either the ForWriting or ForAppending mode.

• For writing (parameter value 2, constant = ForWriting). Files opened in this mode will have new data replace any existing data. (That is, existing data will be deleted and the new data added.) Use this method to replace an existing file with a new set of data.

• For appending (parameter value 8, constant = ForAppending). Files opened in this mode will have new data appended to the end of the file. Use this method to add data to an existing file.

Const ForReading = 1
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\FSO\ScriptLog.txt", ForReading)
Set objFile2 = objFSO.OpenTextFile("C:\FSO\ScriptLog2.txt", 1)

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\FSO\ScriptLog.txt", ForReading)

Listing 4.35 Opening a Text File for Reading

Const ForReading = 1
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\FSO\ScriptLog.txt", ForReading)

Closing Text Files

• Delete the file. As noted previously in this chapter, you might occasionally write scripts that create a temporary file, use that file for some purpose, and then delete the file before the script terminates. If you attempt to delete an open file, however, you will encounter an "Access denied" error because the operating system will not allow you to delete an open file.

• Reread the file. There might be times when you need to read the same file multiple times within a script. For example, you might open a text file, save the entire contents of the file to a string variable, and then search that string for the existence of a particular error code. If the code is found, you might then read the file on a line-by-line basis, extracting each line where the error was recorded.

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\FSO\ScriptLog.txt", 1)
Wscript.Echo "Reading file the first time:"
strContents = objFile.ReadAll
Wscript.Echo strContents
Wscript.Echo "Reading file the second time:"
Do While objFile.AtEndOfStream = False
    strLine = objFile.ReadLine
    Wscript.Echo strLine
Loop

Reading file the first time:
File line 1.
File line 2.
File line 3.
Reading file the second time:

Listing 4.36 Opening and Closing a Text File

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile("C:\FSO\ScriptLog.txt", 1)
objFile.Close