I am trying to edit and view whole "IPTC" data of an image, is there any one-liner command to only list them all? Thanks.
found this command `exiftool all -G1 -a -s 1.JPG`, is it only for view or also updates anything?
Which "IPTC" data? There's the old standard of IPTC IIM, and the newer tags of IPTC core/Ext. But the latter is only part of the IPTC Photo Metadata Standard (https://www.iptc.org/std/photometadata/specification/IPTC-PhotoMetadata), not all of it.
To see all of it, you could use
exiftool -G1 -a -s -IPTC:All -XMP:All /path/to/files/
but there probably would be XMP data in the output that isn't part of the IPTC Photo Metadata Standard.