Rewrite view kernel conf

docs/gemstones/view_kernel_conf.md

@@ -12,86 +12,141 @@ tags:
 
 # View Current Kernel Configuration
 
-The Linux kernel stores running kernel information in two places via special filesystems located in memory:
+The Linux kernel stores running kernel information in two places via special filesystems: ([A summary of them](https://www.landoflinux.com/linux_procfs_sysfs.html))
+
   - The older [procfs](https://man7.org/linux/man-pages/man5/procfs.5.html) which mounts `/proc` (verify via `mount -l -t proc`)
-  - The newer [sysfs](https://man7.org/linux/man-pages/man5/sysfs.5.html) which mounts `/sys` (verify via `mount -l -t sysfs`)
+  - The newer [sysfs](https://man7.org/linux/man-pages/man5/sysfs.5.html) which mounts `/sys`    (verify via `mount -l -t sysfs`)
 
-[Concise summary](https://www.landoflinux.com/linux_procfs_sysfs.html) of them and what info they contain.
+!!! caution
 
-Linux distributions store the config used to compile the kernel as an ASCII file in:
+    Be cautious if examining the files mentioned here, altering them can change the behavoir of the actual running kernel!
 
-```bash
-/lib/modules/<kernel-release>/build/.config
-```
 
-Configured builtin (statically compiled in) and loadable modules for the currently running kernel are listed by directories named for the modules in:
+These two interfaces allow you to view and change the parameters of the currently running kernel.
+Note that if you do an [`ls -l`](https://man7.org/linux/man-pages/man1/ls.1.html) on some of these files, they will show as "0" length, but if you [`cat`](https://man7.org/linux/man-pages/man1/cat.1.html) them out they actually contain data; most of them are
+ASCII and editable, however some are binary, and in either case commands like [`file`](https://man7.org/linux/man-pages/man1/file.1.html) or [`stat`](https://man7.org/linux/man-pages/man2/lstat.2.html) will typically just return "empty file" or "0" for lengths, although they will show you other information.
 
+The preferred and standard programs for interacting with these functions are [`lsmod`](https://man7.org/linux/man-pages/man8/lsmod.8.html), [`modinfo`](https://man7.org/linux/man-pages/man8/modinfo.8.html) and [`sysctl`](https://man7.org/linux/man-pages/man8/sysctl.8.html), among others.
 ```bash
-/sys/module/
+sysctl -a | grep -i <keyword>
+```
+```bash
+lsmod | grep -i <keyword>
+```
+```bash
+modinfo <module>
 ```
 
 See what your currently running "kernel release" version is with:
 
-`uname -r` and substitute its value in commands with `$(uname -r)`
-
-You can examine these files to make sure the currently running kernel was compiled with the functions you need:
-
-  - `cat /lib/modules/$(uname -r)/config | grep -i <keyword>`
-  - `ls /sys/module/ | grep -i <keyword>`
-  - `sysctl -a | grep -i <keyword>`
-  - `lsmod | grep -i <keyword>`
-  - `modinfo <module>`
-
-You can check for kernel module dependencies in:
-
-```bash
-/lib/modules/<kernel-release>/modules.dep
-```
-but it is easier to read the output of the "Used-by" field in `lsmod`.
+`uname -r` and substitute its return value in commands by using `$(uname -r)`
 
 RHEL and derivative distributions (Fedora, CentOS Stream, Scientific Linux, RockyLinux, Almalinux, et. al.)
-also store the config used for bootable installed kernels in the `/boot` directory as ASCII files:
+also store the config used for bootable installed kernels in the `/boot` directory used by Grub2 as ASCII files:
 
 ```bash
 /boot/config-<kernel-release>
 ```
+
 To check the currently running kernel config for a particular value:
 
 ```bash
 cat /boot/config-$(uname -r) | grep -i <keyword>
 ```
 
-Results will show
+Results will show:
   - "=m" if compiled in as a kernel module
   - "=y" if compiled statically into the kernel
-  - "is not set" if the setting exists but is not enabled (a boolean)
-If your search yields no results then the element you are looking for may depend on another config element which
-isn't set (check this with `lsmod`).
+  - "is not set" if that setting was commented out
+  - a numeric value
+  - a quoted string value
 
-Some distributions, like Gentoo and Arch, use `/proc/config.gz` by default instead:
+Some distributions, like Gentoo and Arch, use the `configs` kernel module to provide `/proc/config.gz` by default instead:
 
 ```bash
 zcat /proc/config.gz | grep -i <keyword>
 zgrep <keyword> /proc/config.gz
 ```
 
-For any distribution, if your running kernel has set both
-
-```
-CONFIG_IKCONFIG
-CONFIG_IKCONFIG_PROC
-```
+For any distribution, if your running kernel has set both `CONFIG_IKCONFIG` and `CONFIG_IKCONFIG_PROC`
 and if
 
 ```bash
-ls /sys/module/configs
+ls -lh /sys/module/configs
 ```
+
 exists and is executable (searchable in the case of a dir)
-then you can create `/proc/config.gz` with this command:
+then you can create `/proc/config.gz` with this command if it is not present:
 
 ```bash
 modprobe configs
 ```
+
+!!! Enabled Repos:
+
+    This document does not currently cover kernel packages that might have come from non-default repos such as:
+        appstream-debug, appstream-source, baseos-debug, baseos-source, or devel
+
+
+The `kernel-devel` packages install the config file used to compile each installed standard kernel package as an ASCII file in the following location:
+
+```bash
+/usr/src/kernels/<kernel-release>/.config
+```
+
+This file is more commonly accessed by a symlinked path provided by the `kernel-core` packages:
+
+```bash
+/lib/modules/<kernel-release>/build/ -> /usr/src/kernels/<kernel-release>/
+```
+
+If you have `kernel-debug-devel` packages installed you will also have this directory:
+
+```bash
+ /usr/src/kernels/<kernel-release>+debug/
+```
+
+You can look in any of the following for details on the config values used to build an installed kernel:
+
+```bash
+/lib/modules/<kernel-release>/config
+/lib/modules/<kernel-release>/build/.config
+/usr/src/kernels/<kernel-release>/.config
+/usr/src/kernels/<kernel-release>+debug/.config
+```
+
+Configured modules for the currently running kernel, whether compiled as builtin (i.e. statically into the kernel itself) or a loadable module are listed by sub directories named as the module name in:
+
+```bash
+/sys/module/
+```
+
+For each installed kernel-release you can examine these files to see what values were compiled into that kernel, and what version of [GCC](https://man7.org/linux/man-pages/man1/gcc.1.html) was used to compile it:
+
+```bash
+cat /lib/modules/$(uname -r)/config | grep -i <keyword>
+```
+```bash
+cat /lib/modules/$(uname -r)/build/.config | grep -i <keyword>
+```
+```bash
+cat /usr/src/kernels/$(uname -r)/.config | grep -i <keyword>
+```
+```bash
+cat /usr/src/kernels/$(uname -r)+debug/.config | grep -i <keyword>
+```
+```bash
+ls -lh /sys/module/ | grep -i <keyword>
+```
+
+You can check for kernel module dependencies in the file:
+
+```bash
+/lib/modules/<kernel-release>/modules.dep
+```
+
+but it is easier to read or parse the output of the "Used-by" field in [`lsmod`](https://man7.org/linux/man-pages/man8/lsmod.8.html).
+
 ## Reference:
 
-[sysctl](https://man7.org/linux/man-pages/man8/sysctl.8.html), [lsmod](https://man7.org/linux/man-pages/man8/lsmod.8.html), [modinfo](https://man7.org/linux/man-pages/man8/modinfo.8.html), [modprobe](https://man7.org/linux/man-pages/man8/modprobe.8.html), [depmod](https://man7.org/linux/man-pages/man8/depmod.8.html), [modules.dep](https://man7.org/linux/man-pages/man5/modules.dep.5.html), [procfs](https://man7.org/linux/man-pages/man5/procfs.5.html), [sysfs](https://man7.org/linux/man-pages/man5/sysfs.5.html), [uname](https://man7.org/linux/man-pages/man8/uname26.8.html)
+[depmod](https://man7.org/linux/man-pages/man8/depmod.8.html), [ls](https://man7.org/linux/man-pages/man1/ls.1.html), [lsmod](https://man7.org/linux/man-pages/man8/lsmod.8.html), [modinfo](https://man7.org/linux/man-pages/man8/modinfo.8.html), [modprobe](https://man7.org/linux/man-pages/man8/modprobe.8.html), [modules.dep](https://man7.org/linux/man-pages/man5/modules.dep.5.html), [namespaces](https://man7.org/linux/man-pages/man7/namespaces.7.html), [procfs](https://man7.org/linux/man-pages/man5/procfs.5.html), [sysctl](https://man7.org/linux/man-pages/man8/sysctl.8.html), [sysfs](https://man7.org/linux/man-pages/man5/sysfs.5.html), [uname](https://man7.org/linux/man-pages/man8/uname26.8.html)