EXIFTIME(1)EXIFTIME(1)NAMEexiftime - display or adjust date & time Exif tags; list files ordered
by their Exif date & time tags
SYNOPSISexiftime [-filqw] [-s delim] [-t[acdg]] [-v[+|-]val[ymwdHMS]] file ...
DESCRIPTION
When invoked without arguments, the exiftime utility displays the Exif
date and time tags contained in each input file to the standard output.
Otherwise, depending on the options specified, exiftime will operate on
only the chosen tags, will adjust the date and time, will write an
adjusted time to each file, or will list each file in ascending order
by date and time.
Most digital cameras include one or more date and time tags in the Exif
data added to the image files they produce. These tags are:
Image Created
The date and time the image was created or changed. This is the
most common tag.
Image Generated
The date and time the original image data was generated (i.e., when
picture was taken).
Image Digitized
The date and time the image was stored as digital data.
The format for these tags is "YYYY:MM:DD HH:MM:SS" with the time shown
in 24-hour format. The exiftime utility cannot add a tag if it does
not already exist in file.
By default, exiftime will simply print out any of the three date and
time flags in each input file. The -l flag will produce a listing of
each input file in date/time order, suitable for use in further image
processing (e.g., production of a Web catalog) when filename ordering
is not useful.
The -v flag may be used to vary, or adjust, dates and times. When used
with the -w flag, which writes the adjusted date and time to each input
file, one may, for example, process a batch of files to adjust for a
camera's incorrectly set clock.
OPTIONS-f Write adjusted date and time tags without prompting for confir‐
mation.
-i Output a prompt to standard error before overwriting a date and
time tag with the adjusted value. If the response from the
standard input begins with 'y' or 'Y', the tag is overwritten.
This option is default behavior.
-l List each input file in ascending order by timestamp. By
default, it uses the Image Created tag. In the absence of an
Image Created tag, first Image Generated then Image Digitized
are used. Alternatively, the -t flag may be used to specify the
timestamp preference for ordering. If no date and time tags are
present, the OS's epoch is used. This flag overrides all others
but the -t flag.
-q Do not output details of a date and time adjustment to standard
out when using the -w flag.
-s Separate field name and value with the string delim. The
default is ': '.
-t Select the date and time tags for display or adjustment when
followed by one or more of a (all tags), c (Image Created), d
(Image Digitized), or g (Image Generated).
-v Adjust the date and time tags' second, minute, hour, month day,
week day, month or year according to val. If val is preceded
with a plus or minus sign, the date is adjusted forwards or
backwards according to the remaining string; otherwise the rele‐
vant part of the date is set. The date can be adjusted as many
times as required using these flags. Flags are processed in the
order given.
When providing an absolute value (rather than a relative adjust‐
ment), seconds are in the range 0-59, minutes are in the range
0-59, hours are in the range 0-23, month days are in the range
1-31, week days are in the range 0-6 (Sun-Sat), months are in
the range 1-12 (Jan-Dec) and years are in the range 80-38 or
1980-2038.
If val is numeric, one of either y, m, w, d, H, M, or S must be
used to specify which part of the date is to be adjusted.
The week day or month may be specified using a name rather than
a number. If a name is used with the plus (or minus) sign, the
date will be put forwards (or backwards) to the next (previous)
date that matches the given week day or month. This will not
adjust the date, if the given week day or month is the same as
the current one.
When the date is adjusted to a specific value that doesn't actu‐
ally exist (for example March 26, 1:30 BST 2000 in the
Europe/London timezone), the date will be silently adjusted for‐
wards in units of one hour until it reaches a valid time. When
the date is adjusted to a specific value that occurs twice (for
example October 29, 1:30 2000), the resulting timezone will be
set so that the date matches the earlier of the two times. In
all cases, daylight savings time considerations are ignored.
Refer to the examples below for further details.
-w Write the adjusted date and time tags. By default, any of the
three date and time tags present in the file are adjusted; oth‐
erwise, only those specified with the -t flag are adjusted.
EXAMPLES
The command
exiftime example1.jpg
will display:
Image Created: 2003:09:12 17:05:37
Image Generated: 2003:09:12 17:05:37
Image Digitized: 2003:09:12 17:05:37
The command
exiftime-tcd example1.jpg
will display:
Image Created: 2003:09:12 17:05:37
Image Digitized: 2003:09:12 17:05:37
The command
exiftime -v+3H example1.jpg
will adjust each time forward by three hours and display:
Image Created: 2003:09:12 20:05:37
Image Generated: 2003:09:12 20:05:37
Image Digitized: 2003:09:12 20:05:37
The command
exiftime -v+5d -v-7M -fw -tg *.jpg
will adjust the date ahead five days and the time back seven minutes
and write the adjusted date and time to the Image Generated tag without
a prompt for confirmation for all files that match "*.jpg". It dis‐
plays:
example1.jpg:
Image Generated: 2003:09:12 17:05:37 -> 2003:09:17 16:58:37
example2.jpg:
Image Generated: 2004:01:22 17:07:02 -> 2004:01:27 17:00:02
The command
exiftime-l -tdg *.jpg
will list all files that match "*.jpg", one per line, in ascending
timestamp order. It'll attempt to use the following timestamp values,
in order: Image Digitized, Image Generated, Image Created, and,
finally, the OS's epoch.
DIAGNOSTICS
The exiftime utility exits 0 on success and 1 if an error occurs.
SEE ALSOexiftags(1), exifcom(1)STANDARDS
The exiftime utility was developed using the 2003 draft Exif standard,
version 2.21 (http://tsc.jeita.or.jp/).
BUGS
Does not support the Exif tags SubsecTime, SubsecTimeOriginal, or Sub‐
secTimeDigitized. Does not support manufacturer-specific date and time
tags.
AUTHOR
The exiftime utility and this man page were written by Eric M. Johnston
<emj@postal.net>. The time adjustment functionality and documentation
were derived from portions of FreeBSD's date(1) command by Brian Somers
<brian@Awfulhak.org>.
EXIFTIME(1)
