GNU file utilities
4.4 Time zone items
A time zone item specifies an international time zone, indicated
by a small set of letters, e.g., `UTC' or `Z'
for Coordinated Universal
Time. Any included periods are ignored. By following a
non-daylight-saving time zone by the string `DST' in a separate
word (that is, separated by some white space), the corresponding
daylight saving time zone may be specified.
Time zone items other than `UTC' and `Z'
are obsolescent and are not recommended, because they
are ambiguous; for example, `EST' has a different meaning in
Australia than in the United States. Instead, it's better to use
unambiguous numeric time zone corrections like `-0500', as
described in the previous section.
