Redirecting command output to files

Windows command-line programs normally display their output in the Command Prompt window. Using output redirection, you can instead save the output into a file. This can be very useful.

To save the output to a file, use the greater than character (>). For instance:

dir > files.txt

Instead of displaying the directory listing on the screen, Windows writes it into files.txt. You need to be careful however: if the destination file already exists, > replaces its contents.

To append output to an existing file, use two greater than characters:

dir >> files.txt

Redirection becomes particularly useful with diagnostic commands:

ipconfig /all > network.txt
ping server >> network.txt

You can then examine the results with a text editor, archive them, or send them to somebody helping diagnose the problem.

Output can also be passed directly from one command to another using the pipe character (|). For example:

dir | more

This displays a long directory listing one screen at a time. I like to do this when writing batch files or collecting command-line diagnostic information.

Hope this helps!