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What are Linux headers? Why are there two headers namely 3.5.0-34 and 3.2.0-48 in my latest Ubuntu update (just an observation).

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Note that you can remove these old headers:… – Justin Jul 16 '13 at 15:51

These packages contain files that are part of the source code of the Linux kernel, available under /usr/src if you would like to take a look. They are just the makefiles and header files (file extension .h), which define the public API of the kernel, which is needed to compile programs that interact with the kernel directly (two examples that come up in internet searches are device drivers and virtualization software).

You have two versions because one is for your current kernel and the other is for an older kernel that you used previously. Ubuntu by default is very conservative with kernel-related files and takes a number of precautions to avoid removing them when they are still needed, and sometimes this results in a gradual accumulation of such packages as new versions are installed.

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Thank you, that was a very good answer. – Srikanth Suresh Jul 19 '13 at 15:19

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