Concatenate Files in Windows - Keyboard Ninja

Combining Multiple Log Files into a Single File

When dealing with numerous log files, the need to consolidate them for analysis in tools like Excel or a database often arises. Manually opening and copying data from hundreds of files is impractical. Fortunately, a solution exists using the command line.

The key lies in utilizing the "for" command within a DOS environment. This command allows for the automated execution of a specified action on a series of files.

Understanding the "for" Command Syntax

The basic structure of the "for" command is as follows:

for in () do

This syntax instructs the system to iterate through each file listed in the specified directory and execute the defined command on each one.

To combine all .log files within a directory into a single file, the "type" command is employed, directing the output to a new file using the append operator.

Appending vs. Overwriting Files

It’s crucial to understand the difference between the >> and > operators. The >> operator appends data to the end of an existing file.

Conversely, the > operator completely overwrites the file's contents. For the purpose of consolidating log files, appending is essential to avoid data loss.

The Command to Aggregate Log Files

Assuming you are currently located in the directory containing the log files, the following command will achieve the desired result:

for %f in (*.log) do type "%f" >> aggregate.txt

This command iterates through each .log file, outputs its contents using the "type" command, and appends those contents to a file named aggregate.txt.

This technique was recently applied in a work project, prompting the creation of this guide. The efficiency of this method proved invaluable.

A curious consideration: the visual representation of a "DOS hat" remains an amusing thought experiment.