Update the time stamp string(s) in the buffer.
A template in a file can be automatically updated with a new time stamp
every time you save the file. Add this line to your init file:
(add-hook 'before-save-hook 'time-stamp)
or customize `before-save-hook' through Custom.
Normally the template must appear in the first 8 lines of a file and
look like one of the following:
Time-stamp: <>
Time-stamp: " "
The time stamp is written between the brackets or quotes:
Time-stamp: <2001-02-18 10:20:51 gildea>
The time stamp is updated only if the variable `time-stamp-active' is non-nil.
The format of the time stamp is set by the variable `time-stamp-pattern' or
`time-stamp-format'. The variables `time-stamp-pattern',
`time-stamp-line-limit', `time-stamp-start', `time-stamp-end',
`time-stamp-count', and `time-stamp-inserts-lines' control finding
the template.
(fn)