July 28 – August 7, 2026 — an 11-day segment
Day 42 turned out to be the longest single working day on record for this project — eleven calendar days under one session label, covering three distinct threads: closing out the entire EXPANDED index-build queue on the LearnLinux site, chasing down and resolving a genuine mystery in the site's own tooling, and building a brand-new breadcrumb system from scratch and rolling it out across both the LearnLinux and AI Education sites.
Started from a Day 41 check_tree.sh -a sweep that flagged a long list of EXPANDED subdirectories with orphaned content and no landing page. Worked through the list smallest-to-largest, building 19 index pages in total:
Bash, SystemD, BashSpecial, LAMPS, Network, NetworkManager, Cron-Scheduling, SED-AWK, Editors, Keyboard, Filesystem, NumberSystems, Containers, Performance, Users-Groups, Logging, SELinux, Storage, Security, Fundamentals, VI, ServerMgmt — every one confirmed clean via vnu and check_tree.sh -a.
check_tree.sh -a was always being run scoped to a single subdirectory, so anything linked only from a parent hub page (like Learn_by-catagory.html or EXPANDED/index.html) would show as "orphaned" even though it was perfectly reachable. Not a script bug — just a reminder to check the parent hub pages before assuming a rebuild is needed.
Established a consistent house style along the way: slate-dark gradient headers, amber accent color, numbered badge cards for multi-part series, and a black-background/white-text inline treatment for footer back-links so they'd stay legible regardless of a page's own color scheme.
i&1 MysteryA full-tree recursive check_tree.sh -a sweep surfaced 62 identical zero-byte files, one per directory touched, all sharing a filename that displayed as i&1 in every terminal. Deleting them by name kept silently failing — find -name 'i&1' matched nothing, even though the files were clearly there.
The breakthrough: find -type f -empty found all 62 instantly. Since that test matches on file content, not name, it proved the real filename wasn't the literal characters i, &, 1 at all — something in the name was a hidden or non-ASCII byte that just happened to render that way. Cleaned up safely with a NUL-delimited find -print0 | xargs -0 pipeline, after saving a pre-delete tar as a safety net. The exact origin inside check_tree.sh was never fully traced, but the files are gone and the tree is clean.
Built add-bc.pl from scratch, iterating through several real problems as they surfaced in actual use:
*-index.html fallbacks) instead of hardcoding any one site section-d <dir> (directory), -f <file> (link target), -n N (depth) — renamed from an earlier -p/-i/-d scheme once the letters started colliding. as the directory argument used to make Perl's dirname('.') return . literally, breaking the rendered label — fixed via Cwd::abs_path()Companion tool Find-file-NO-breadcrumb.sh reports both the missing-breadcrumb file list and the parent directory's actual index filename in one pass, so there's no guessing before running add-bc.pl.
Deployed across the AI Education site in full: three root-level files, the collaboration-index.html landing page, and all seven collaboration content files. Along the way, found and fixed a genuine duplicate — collaboration/index.html and collaboration-index.html had drifted into two independently-edited copies of the same page. Collapsed back to one real file plus a symlink, matching the site's established convention.
check_tree.sh -a on /AI:
Breadcrumb work also touched substantial parts of LearnLinux's EXPANDED and CMDS directories. Considered done-for-now as of Day 42 close — the much larger remaining scope (cmds/commands at ~150 files, CMDS at ~200 files, the lowercase expanded/ tree, and LP/) is parked for whenever it's worth picking back up.
target= attributes had been mistakenly applied to same-page #anchor linksprocessed/*.html.tgtrun files site-widecmds/commands at 121, building-in-public at 68) were both non-issues, not real gapscommands design question — search-only by design, or a genuine gap?.tgtrun skip pattern to check_tree.sh's skip-listBAT anchor in the CMDS command navlessons-learned.html still unrecorded for Days 11–42Full detail in 2DO-LIST-DAY43.html.