Path: csiph.com!optima2.xanadu-bbs.net!xanadu-bbs.net!news.glorb.com!usenet.stanford.edu!not-for-mail From: Linda Walsh Newsgroups: gnu.bash.bug Subject: Re: -e does not take effects in subshell Date: Tue, 18 Aug 2015 15:31:03 -0700 Lines: 47 Approved: bug-bash@gnu.org Message-ID: References: <20150811135056.GD4309@eeg.ccf.org> <55CC26A7.10000@redhat.com> <55D39A71.2030109@tlinx.org> <20150818210043.GK4309@eeg.ccf.org> NNTP-Posting-Host: lists.gnu.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: usenet.stanford.edu 1439937411 28635 208.118.235.17 (18 Aug 2015 22:36:51 GMT) X-Complaints-To: action@cs.stanford.edu Cc: "bug-bash@gnu.org" To: Greg Wooledge Envelope-to: bug-bash@gnu.org User-Agent: Thunderbird In-Reply-To: <20150818210043.GK4309@eeg.ccf.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] X-Received-From: 173.164.175.65 X-BeenThere: bug-bash@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Bug reports for the GNU Bourne Again SHell List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Xref: csiph.com gnu.bash.bug:11388 Greg Wooledge wrote: > On Tue, Aug 18, 2015 at 01:49:53PM -0700, Linda Walsh wrote: >> Ex: rmx -fr (alias to rm --one-file-system -fr, since rm lacks the >> -x switch like 'find, cp, mv, et al.) no longer works to clean >> out a directory && stay on *one* file system. > > When did POSIX or any historical Unix rm have a --one-file-system option? > You say "no longer works" as if it had EVER worked in the past. --- Historically, linux had it going back to early 2000's (linux being a *nix platform) -- but historically, it wasn't so easy to have features like 'bind/rbind', snapshots, multiple virtual machines that need their own root (or chroot), etc. If you go back far enough symlinks weren't even around. I'm only talking about POSIX ~2001 or before. After that it started changing. So it depends on how historical you are talking. POSIX cmd language started with POSIX.2 in 1992, before that it was purely a programming API. It started including the cmd's as a way of providing portable shell scripts. Not as a way of restricting users. While POSIX changed the 'rm' algorithm to no longer do depth-first removal (now it's 2-pass, depth-first permissions check, then depth-first removal). But that's not the behavior of the historical 'rm'. Various "one-file-system" cp -x, find -x, du -x were added after it became common to allow more complicated mount structures. I remember an early version of cygwin-coreutils-rm on Win7 that didn't recognize symlinks or mountpoints (linkd/junctions) wandering up out of the "C:\recycle bin" over to a documents folder on another computer... Daily-backups do come in handy. > And yes, the standard way to do this (the only way with traditional > tools) would use find ... -xdev ... -exec rm {} + --- Which won't reliably work if your starting path is "pathname/." but would with an rm -frx (or rmx -fr path/.").