How are kernel environment variables used?

[pjp]

After setting them, I expected this to work:

[Goverp]

I ended up writing a script to handle this, as documented in a wiki page, which might be helpful.
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Greybeard

[Hu]

Setting INSTALL_PATH and INSTALL_MOD_PATH in the environment has always worked for me. I use KBUILD_OUTPUT, not O to influence the output directory though. As I read the Makefile, there is special logic to respect O only if it is assigned on the command line:

[pjp]

@Goverp,

Thanks, I may eventually make a script too. I suspect that won't be a problem. For when a step fails though, it seems like having the manual method would be helpful.

@Hu,

Thanks, I'll try some more stuff. I originally used KBUILD_OUTPUT, but that didn't work so I switched to O (several years ago by now).

I don't recall if manually using export <varname> ever worked, but wanting to automate it, I switched to creating an environment variable script that sets the variables, then exports them. Both echo and printenv work with those variables, so that seems like it should work.
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[Hu]

I set all of $KBUILD_OUTPUT, $INSTALL_PATH, and $INSTALL_MOD_PATH via a helper script that then starts a subshell with those in its environment. This has worked reliably for me for a long time.

[pjp]

Well, using KBUILD_OUTPUT worked for 'menuconfig.' I was going to wait until the next stable version to update, but who knows when that will happen, so I'll probably try this week.

Interesting that O doesn't work (and seemingly INSTALLKERNEL).
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