Insert current date or time

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Tip: #97 - Insert current date or time

Created: August 9, 2001 Complexity: basic Author: newbie Version: 6.0 Karma: 185/81 Imported from: Tip#97

There are a variety of ways to automatically add a date/time stamp to your editing buffer, similar to <F5> in Windows Notepad.

Using strftime()

Vim's internal strftime() function (:help strftime()) returns a date/time string, given a format string, but this might not work on all systems. To store return value of this Vim function for pasting, the "= register (:help "=) is used. Here's a bunch of examples:

In normal mode, this will paste the current datestamp (press the Enter key where you see <Enter>):

"=strftime("%c")<Enter>p

This makes <F5> in insert mode paste a datestamp (:help i_CTRL-R):

:imap <F5> <C-R>=strftime("%c")<CR>

This makes dts typed in insert mode expand to a datestamp (:help abbreviations):

:iab dts <C-R>=strftime("%c")<CR>

To embed the current date in a substitution:

:s/text to replace with date/\=strftime("%c")/

Vary the format string, i.e. the "%c" argument to strftime(), to get the time and/or date in a different format. Depending on the format string used, the result may depend on your locale (:help :language).

The specification for the format string itself depends on the implementation of strftime() on your platform. For details, Unix users may refer to the strftime(3) man page, by running 'man 3 strftime' at the prompt.

Some strftime() format string examples

Format String              Example output
-------------              --------------
%c                         Thu 27 Sep 2007 07:37:42 AM EDT (depends on locale)
%a %d %b %Y                Thu 27 Sep 2007
%b %d, %Y                  Sep 27, 2007
%d/%m/%y %H:%M:%S          27/09/07 07:36:32
%H:%M:%S                   07:36:44
%T                         07:38:09
%m/%d/%y                   09/27/07
%y%m%d                     070927 

RFC822 format:
%a, %d %b %Y %H:%M:%S %z   Wed, 29 Aug 2007 02:37:15 -0400

ISO8601/W3C format (http://www.w3.org/TR/NOTE-datetime):
%FT%T%z                    2007-08-29T02:37:13-0400

Using external tools

Unix users have access to the date utility. You may ask Vim to run 'date' and insert the output in the buffer:

:r!date

Under Windows,

:r!date /t

Alternatively, Windows users may install cygwin from http://sources.redhat.com/cygwin for access to Unix 'date' and a host of other utilities, but that might be overkill if you're just looking for datestamps.

Automatically update timestamps

You might want to automatically update existing time stamps when writing a file.

This is a solution for html implemented as an autocmd which fires when the file is written:

:au BufWritePre *.html exe "norm mz"|exe '%s/\(<!-- DATE -->\).\{-}\d\d:\d\d:\d\d/\1'.strftime("%b %d, %Y %X")."/e"|norm `z

That way a string of the form <!-- DATE -->Aug 13, 2001 14:19:50 is embedded in the text, and it will be updated to the current date (using Vim's built-in strftime() function) and time automatically – every time I save the file (the ...DATE... stuff is an HTML comment which won't appear in an HTML document).

This is a general solution:

" Add a function that returns a time stamp in the desired format.
if !exists("*TimeStamp")
  fun TimeStamp()
    return "Time-stamp: <" . strftime("%d %b %Y %X") . " My Name>"
  endfun
endif

" Search for an existing time stamp and update it.
if !exists("*UpdateTimeStamp")
  fun UpdateTimeStamp()
    if (match(getline(1),"Time-stamp: <.*>")) > 1
      exe "1,1 s/Time-stamp: <.*>/" . TimeStamp()
    endif
  endfun
endif

" Abbreviation to manually enter a timestamp (type YTS in insert mode).
iab YTS <C-R>=TimeStamp()<CR>

" Add an autocommand to update an existing time stamp when writing the file.
" It uses the functions above to replace the time stamp and restores cursor
" position afterwards.
autocmd BufWritePre,FileWritePre * ks|call UpdateTimeStamp()|'s

The date is searched for in the first line of the file only (you can change that) in columns > 1. I did that mainly for security reasons (in source code, there will be almost always a comment start, e.g. /* in c, preceding the time stamp).

Comments

I mapped the time function in vimrc:

map T "=strftime("%m/%d/%y %H:%M")<CR>p

The leading quotation mark is necessary and there is no closing quote.

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as well as these "= commands:

" in normal mode, paste before cursor position, allows date insertion
" at the start of the line.
nmap <leader>tt "=strftime("%x %X (%Z) ")<CR>P

" in insertmode, esc to normal, paste, and return to insert
imap <leader>tt <Esc>"=strftime("%x %X (%Z) ")<CR>Pi

You could also use the following :execute commands:

nmap <leader>tt :execute "normal i" . strftime("%x %X (%Z) ")<Esc>
imap <leader>tt <Esc>:execute "normal i" . strftime("%x %X (%Z) ")<Esc>i

By default, <leader> is "\", but it's a variable you can modify. In my case I hit "\tt" in normal or insert mode and hello time and date. See "man strftime" to find replacements for the date format "%x %X (%Z)".

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