exiftool
Find metadata.
exiftool image.jpg
Find info on all images in current directory.
exiftool -ext .png .
You can make this recurring with the -r switch.
And overwrite all metadata:
exiftool -all= -overwrite_original -ext jpg .
(NB: This does not work on pdf data. See here for erasing all pdf data)
Or just GPS data:
exiftool -gps:all= *.jpg
You can also use the imagemagick tool:
identify -verbose