Professional Windows® PowerShell

19.5. Redirection

Windows PowerShell has two redirection operators, > and >>. A redirection operator redirects the output of a command (or pipeline) to a specified location. The > operator creates a new file and redirects text to it or, if the file exists, it overwrites the existing content. The >> operator appends text to an existing file without overwriting the existing content.

You can redirect text from the command line to a file. For example, to redirect the literal text Hello world! to a not yet existent file NonExistent.txt in the same directory use this command:

"Hello world!" > NonExistent.txt

You can check that the content has been added to the newly created file using the command:

get-content NonExistent.txt

If you then redirect new text to the file using the > operator, it overwrites the existing content, as you can demonstrate using the following commands:

"This overwrites the old text." > NonExistent.txt
get-content NonExistent.txt

But, if you use the >> operator, you can append text to the file, as you can demonstrate using the following commands:

"This appends a new line to the file." > NonExistent.txt
get-content NonExistent.txt

Figure 19-20 shows the results of executing the preceding commands in this section.

Figure 19.20. Figure 19-20

Similarly, you can use the >> redirection operator to append text to an existing file, as shown in Figure 19-20 when you execute ...