Unbuf

unbuf is a command-line utility found on Unix-like operating systems. Its primary function is to disable buffering for a specified file or device. When a file or device is buffered, data is held in memory and written out in larger chunks, which can improve performance but may lead to delays in seeing changes. By using unbuf, this buffering behavior is turned off, ensuring that data is written to its destination immediately as it is produced.

This can be particularly useful in scenarios where real-time output is critical. For example, when redirecting the output of a program to a file that is being monitored by another process, unbuf can ensure that the monitoring process receives the data as soon as it's generated by the source program, rather than waiting for the buffer to fill. It is often employed in shell scripting to control the flow of data for debugging or interactive applications. The typical usage involves piping the output of a command through unbuf and then to another destination.