overwrite all dates and times with current date via command line

[datetime]

Hello

I struggle to find a solution and read many posts which i found via google, including on this forum.
Nothing helped so i signed up.

First: I want to set the CURRENT date & time via command line. I dont know how to get current time correctly.

Second: I want to overwrite many files with the current time, but only the tags it finds, which are very different! So i dont want to simply modify "DateTimeOriginal" or something, i want to also modify IF IT EXISTS IN THAT FILE things like SonyDateTime2 etc. etc. but i DONT want to add that time tag if it doesnt already exist!
also i dont want to remove those additional time tags UNLESS they have no valid time format (SubSecTimeOriginal              : 678480 for example) or if they simply cant be modified by exiftool.

Thank you SO MUCH in advance i'm banging my head on this for 4 hours now!

[Phil Harvey]

First: I want to set the CURRENT date & time via command line. I dont know how to get current time correctly.

exiftool -now FILE

Second: I want to overwrite many files with the current time, but only the tags it finds, which are very different! So i dont want to simply modify "DateTimeOriginal" or something, i want to also modify IF IT EXISTS IN THAT FILE things like SonyDateTime2 etc. etc. but i DONT want to add that time tag if it doesnt already exist!

exiftool -wm w -time:all=now DIR

also i dont want to remove those additional time tags UNLESS they have no valid time format (SubSecTimeOriginal              : 678480 for example) or if they simply cant be modified by exiftool.

I'm not sure what you want here.

- Phil

[datetime]

THANKS simpler than i thought

Encountered some other thing i dont get done by myself:
looking to overwrite it all with each files create date
-wm w -time:all<filecreatedate
-wm w "-time:all<filecreatedate"
-wm w -time:all=<filecreatedate
-wm w "-time:all=<filecreatedate"
-wm w -time:all=filecreatedate
-wm w "-time:all=filecreatedate"

didnt work

what shall i do, sir?

also i checked, and the "now" command didnt work for "samsung timestamp" i can only remove this with the trailer= function right?

[StarGeek]

See Common Mistake #5, 'exception to rule "b" '

This should work.  Swap the double quotes for single quotes if you're on Mac/Linux
-wm w "-time:all<$filecreatedate"

[datetime]

THANK YOU, Works

used: exiftool -wm w "-time:all<$filecreatedate" -overwrite_original *.jpg


But on some files it modifies certain tags, but drops them on others completely, where they are just gone?! especially the SubSec stuff:

[Composite]     SubSecCreateDate                : 2021:02:19 08:41:18+01:00
[Composite]     SubSecDateTimeOriginal          : 2021:02:19 08:41:18+01:00
[Composite]     SubSecModifyDate                : 2021:02:19 08:41:18+01:00

so one some it works, on some it deletes.

if it helps:
got many errors like
Warning: Can only set MDItem tags on OS X
Warning: [minor] Unrecognized MakerNoteUnknown
Warning: [minor] Maker notes could not be parsed
Warning: Invalid EXIF text encoding for UserComment
Warning: [minor] Entries in IFD0 were out of sequence. Fixed.

[Phil Harvey]

The Now tag doesn't include subseconds.  You can use the -v2 option and write a tag by itself to see what is happening.  For example, SubSecDateTimeOriginal is a Composite tag that is based on the values of 3 EXIF tags:

Code Select Expand

> exiftool a.jpg -subsecdatetimeoriginal=now -v2
Writing Composite:SubSecDateTimeOriginal
Deleting ExifIFD:SubSecTimeOriginal
Writing ExifIFD:DateTimeOriginal
Writing ExifIFD:OffsetTimeOriginal
...

or just writing one of the EXIF SubSec tags directly:

Code Select Expand

> exiftool a.jpg -subsectimeoriginal=now -v2
Warning: Error converting value for ExifIFD:SubSecTimeOriginal (ValueConvInv)
Nothing to do.

- Phil

[datetime]

But how do i do it that it ONLY modifies the tag if it exists? I dont want to add it, if it does not exist. Thank you!

[StarGeek]

The -wm (writemode) option in the above commands does this.  The w argument to this option only allows for writing of existing tags.  It will not create new tags (g) or new groups (c).

[datetime]

solved.