Building a progress indicator for the Comm utility

Today I found myself needing to use the comm utility to compare two 20GB files. This ended up taking about 10 minutes and while it was running I got curious at how much time was left. Knowing that comm must read through both files before it finishes, I decided to see if I could build a simple progress indicator based on the read offset of one of it’s file descriptors.

I jumped straight into the /proc filesystem and discovered the fdinfo directory. This directory contains a file for each of the process’ file descriptors indicating the offset, file mode and mount ID. …

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Drew Stokes

I turn beer into software. Be good humans.

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