2024-03-13

Exiftool is more versatile than I'd realised. 
Good for pdfs too.

# set 'Author' 
exiftool -Author=Myself  f.pdf 

# shift dates a day later 
exiftool -alldates+=24  f.pdf

# shift dates 31 days earlier
exiftool -alldates-=$((31*24))  f.pdf



# for these operations it's a lot more handy than my previous choice of:

	pdftk "$in" dump_data_utf8  >info.tmp 
	... something to edit the info.tmp file 
	pdftk "$in" update_info_utf8 info.tmp output "$out"