Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!ucrmath!alchemy!bbs
From: bbs@alchemy.UUCP (BBS Administration)
Newsgroups: comp.unix.programmer
Subject: File "type"
Message-ID: <171@alchemy.UUCP>
Date: 23 Sep 90 03:36:58 GMT
Reply-To: bbs@alchemy.UUCP (BBS Administration)
Organization: Alchemy Software Designs
Lines: 32


	Could someone explain how the command "file" works? Specifically, I am
writing a program that allows users to navigate their $HOME directory and
any subdirectories (they cannot leave their $HOME directory though, for
security reasons) to find files that are to be read into a text editor.
Some text editor forks this program, and when the user selects a file to
read, it writes the pathname to a temporary file which the editor reads 
and then loads into its' buffer.

	I wrote this "navigator" program as a separate entity, so that either
my line based editor (non-curses) or my full screen editor (subset of
curses) can call upon it and use its facilities (the navigator does lots
of other things too) without giving the user shell access directly.
Anyhow, once they select a file for reading, I'd like to be able to
determine if the file is "ascii text" as the program "file" reports
when this is true, and if not, inform the user that the contents are
NOT ascii text and that they may want to reconsider.

	Should I make a pass through the contents and make sure that each
character has the high bit OFF (so it's 7-bit data) or what? I don't
need to determine what kind of file it is, just whether or not it's
something the editors will "like."

Thanks in advance!

-- John

John Donahue, Senior Partner | UUCP: ucrmath!alchemy!{bbs, gumby}  | The Future
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