[TUHS] success, bj assembled and linked in Unix v5

Norman Wilson norman at oclsc.org
Sun Jun 14 11:08:48 AEST 2015

Mark Longridge:

  chmod 0744 bj

Dave Horsfall:

  That has to be the world's oddest "chmod" command.


Not by a long shot.

Recently, for reasons related both to NFS permissions and to
hardware testing, I have occasionally been making directories
with mode 753.

At the place I worked 20 years ago, we wanted a directory
into which anonymous ftp could write, so that people could
send us files; but we didn't want it to become a place for
creeps to stash their creepy files.  I thought about the
problem briefly, then made the directory with mode 0270,
owned by the user used for anonymous ftp and by a group
containing all the staff members allowed to receive files
that way.  That way creeps could deposit files but couldn't
see what was there.

I also told cron to run every ten minutes, changing the
permissions of any file in that directory to 0060.

Oh, and I had already maniacally (and paranoiacally)
excised from ftpd the code allowing ftp to change permissions.

I admit I can't think of a reason to use 744 offhand, since
if you can read the file you can copy it and make the copy
executable.  But UNIX permissions can be used in so many
interesting ways that I'm not willing to claim there is no
such reason just because I can't see what it is.

Norman Wilson
Toronto ON

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