Version 0.2.1 behavior is documented here. Thesupport record separates local verification frompublished MoonX behavior; moonx examples use registry releases.
Print the last lines or bytes of files or stdin:
printf '1\n2\n3\n4\n' | moonx cli/tail -n 2
printf '1\n2\n3\n4\n' | moonx cli/tail -n +3 # from line 3 to the end
moonx cli/tail -n 100 huge.log
Options: -n N last N lines (default 10), -n +K from line K, -c N lastN bytes, -c +K from byte K, -q/-v header control, -f/--follow tofollow an open file descriptor, and -s SEC/--sleep-interval SEC to set thepolling interval (default 1 second).
The observed file paths produced the requested line/byte suffixes and +Kforms. Follow mode emits the initial selection, then emits bytes appended toeach regular file. A file truncated in place is followed from byte zero. Thedescriptor remains open across renames, matching tail -f; deleting andrecreating a path is not followed, because -F is not implemented.
-F remains a tested status-2 rejection. Faithful replacement detection needspublic file identity, which the released filesystem API does not expose;reopening a path is available but alone does not establish that the file wasreplaced. See ADR-0004.
With no file operand, -f silently reads stdin through EOF and exits, matchingthe upstream finite-pipe behavior. Regular-file follow is polling-based andworks on the native and Wasm targets; it does not require host file-notifyAPIs.
Standalone --version prints exactly tail 0.2.1 followed by onenewline. Standalone --help starts with Usage: tail, lists bothmetadata options, and ends with a newline. Both write to stdout, leave stdinunread, and exit with status 0. Exact-version publication and verificationremain recorded separately in the support record.