head コマンドオプションと man ファイルの読み込み

デフォルトでは、以前のバージョンとの互換性フラグが見つかりました。 （正直言って、それが存在するのか全く知りませんでした。）

マニュアルページから：

SEE ALSO
       The  full documentation for head is maintained as a Texinfo manual.  If the info and head programs
       are properly installed at your site, the command

              info coreutils 'head invocation'

coreutils情報ページの下部に：

For compatibility `head' also supports an obsolete option syntax
`-COUNTOPTIONS', which is recognized only if it is specified first.
COUNT is a decimal number optionally followed by a size letter (`b',
`k', `m') as in `-c', or `l' to mean count by lines, or other option
letters (`cqv').  Scripts intended for standard hosts should use `-c
COUNT' or `-n COUNT' instead.  If your script must also run on hosts
that support only the obsolete syntax, it is usually simpler to avoid
`head', e.g., by using `sed 5q' instead of `head -5'.

An exit status of zero indicates success, and a nonzero value indicates failure.