You should always check the man pages if you are in trouble.
Which should read something like this:
Exclude specified tag from extracted information. Same as the -x
option. May also be used following a -tagsFromFile option to
exclude tags from being copied, or to exclude groups from being
deleted when deleting all information (ie. "-all= --exif:all"
deletes all but EXIF information). But note that this will not
exclude individual tags from a group delete. Instead, individual
tags may be recovered using the -tagsFromFile option (ie. "-all=
-tagsfromfile @ -artist"). Wildcards are permitted as described
above for -TAG.
exiftool -overwrite_original -all= -tagsFromFile @ -title -caption -keywords /Users/andyl/photos/*.jpg
should work. Ensure that the tags really are named this way using
What the command does?
-all= deletes all the tags,
-tagsFromFile @ takes the listed flags from the source file, in this case
@ represents the current file, (you could of course substitute with a fixed file here like
-tagsFromFile pic.jpg) and writes them to the destination.