Re: Tail +N apparent error.

[Alfred M. Szmidt]

tail +n is a obsolete syntax, and was deprecate in POSIX 1003.1-2001.
>From the coreutils manual:

| Standards conformance
| ==========================
|
| In a few cases, the GNU utilities' default behavior is incompatible
| with the POSIX standard.  To suppress these incompatibilities, define
| the `POSIXLY_CORRECT' environment variable.  Unless you are checking
| for POSIX conformance, you probably do not need to define
| `POSIXLY_CORRECT'.
|
|    Newer versions of POSIX are occasionally incompatible with older
| versions.  For example, older versions of POSIX required the command
| `sort +1' to sort based on the second and succeeding fields in each
| input line, but starting with POSIX 1003.1-2001 the same command is
| required to sort the file named `+1', and you must instead use the
| command `sort -k 2' to get the field-based sort.
|
|    The GNU utilities normally conform to the version of POSIX that is
| standard for your system.  To cause them to conform to a different
| version of POSIX, define the `_POSIX2_VERSION' environment variable to
| a value of the form YYYYMM specifying the year and month the standard
| was adopted.  Two values are currently supported for `_POSIX2_VERSION':
| `199209' stands for POSIX 1003.2-1992, and `200112' stands for POSIX
| 1003.1-2001.  For example, if you have a newer system but are running
| software that assumes an older version of POSIX and uses `sort +1' or
| `tail +10', you can work around any compatibility problems by setting
| `_POSIX2_VERSION=199209' in your environment.