Re: searching non plain text files

> On Dec 16, 2018, at 6:20 PM, Jonesy via php-general <php-general@lists.php.net> wrote: > > On Sun, 16 Dec 2018 20:16:08 -0500, John wrote: >> On Sun, 2018-12-16 at 14:33 -0500, Tedd Sperling wrote: >>>> On Dec 14, 2018, at 11:19 PM, Jeffry Killen <jekillen@prodigy.net> wrote: >>>> >>>> >>>> Can anyone point me to instruction/advice about >>>> opening and reading files that are not plain text: >>> >>> Jeffry: >>> >>> I don’t know if this will help you, but most “honest” files have a header that >>> states what it is. >>> >>> Try using a hex-editor app and observing the first 10 characters in their >>> headers (i.e., start of the file). For example, a PDF file will state ‘PDF’, a >>> jpg will state ’JFIF’, a rtf file will state ‘rtf’, a zip file will state >>> ‘PK”, a png will state ‘PNG”, and so on. >>> >>> From that observation, you might try working with bin2hex or dechex and other >>> such bin/hex functions PHP provides to check what the file type is in the >>> header and what it reports itself to be in the extension. >>> >>> Additionally, you can always Google it. >>> >> Just to confuse the issue, both zip files and odt (Open Document) files have the >> 'PK' header id. Looking around for some other formats, I found that most tgz >> files (tar, gzipped) have 'vV' followed by the file name (but not all of them!). >> So Jeffry will have to do some sort of a secondary test to be sure. > > Do a search on "magic bytes". > > Jonesy > -- Thank you all for suggestions and ideas; Jeff K