[qodelicious]

procps-ng sysctl prints every variable under a key that is a directory, like sysctl kernel.random. We only did that with -N, and without it we tried to read the directory and failed with "Is a directory".

Now a directory key is expanded to its variables for every mode, so the normal key = value output and -n both work. The -N path is the same as before. Added a test for kernel.random and -n kernel/random.

Fixes #830

[codecov]

Codecov Report

❌ Patch coverage is 38.09524% with 26 lines in your changes missing coverage. Please review.
✅ Project coverage is 19.85%. Comparing base (67832aa) to head (b3b3539).
⚠️ Report is 24 commits behind head on main.

Files with missing lines	Patch %	Lines
src/uu/sysctl/src/sysctl.rs	0.00%	26 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #831      +/-   ##
==========================================
+ Coverage   19.20%   19.85%   +0.65%     
==========================================
  Files          68       68              
  Lines       10156    10306     +150     
  Branches      546      552       +6     
==========================================
+ Hits         1950     2046      +96     
- Misses       8206     8260      +54     

Flag	Coverage Δ
macos_latest	7.01% <ø> (+0.26%)	⬆️
ubuntu_latest	20.21% <38.09%> (+0.66%)	⬆️
windows_latest	0.02% <ø> (-0.01%)	⬇️

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[sylvestre]

what happens with sysctl vm? vm.drop_caches is write-only, so i guess we print an error and exit 1.
procps-ng skips unreadable keys silently. Could be a follow-up together with -a.

[sylvestre]

Thanks for your PR