Addresses a broad audit of built-in shell utilities against their real counterparts: timeout gains signal delivery, -s/-k/--preserve-status/--foreground/-v, and GNU exit codes; diff defaults to normal format and gains -w/-b/-B/-i/-c/-x/-L/-s/--strip-trailing-cr and proper -r gating; find fixes -newerXY timestamp comparison direction, anchors -regex to whole paths, and gains BSD -perm +mode, -type lists, -size T/P suffixes, -E/-x/-s flags; date gains BSD -r epoch, -v adjustments, -j -f strptime, and non-greedy -I; tail/head accept obsolete -N/+N at any position with any file count; rg resolves case flags by last occurrence and gains --path-separator and clean -0 output; stat prints integer epochs for %X/%Y/%Z and gains BSD -s/-x/-t; cksum is registered as a builtin; truncate implements -o/--io-blocks and b/= size suffixes; sleep/timeout accept infinity; yes/errno/kill accept hyphen-prefixed operands; nohup -- cmd no longer runs --; which gains BSD -s.
- Updated the nightly rust toolchain channel in rust-toolchain.toml to nightly-2026-07-28.
- Adopted slice chunking and multiple-of helper methods across native and vendor crates.
- Replaced option map adapters and conditional patterns with idiomatic combinators.
- Added a `SpawnObserver` trait to intercept freshly spawned external command PIDs and process group IDs.
- Exposed `set_spawn_observer` and `spawn_observer` on `ExecutionParameters` to allow tracking process lifecycles.
- Triggered the observer on successful external command execution unless the process is detached or reparented.
can1357