There is nothing more worthy of contempt than a man who quotes himself - Zhasper, 2004
On Sun, Dec 14, 2008 at 11:38 PM, R.G.Salisbury <[email protected]> wrote: > Just sharing a gotcha with "rsync" that caused me big trouble ... > > what's nasty about rsync ? .. > .. which may cause devastating consequences. > > rsync is in my opion the best thing since sliced bread... but be careful. > > > > CLI commands -- cp, rcp, scp, rsync, all have similarites > BUT there are some nasty gotcha's when switching from one to another. > > You probably noticed some oddities , but had worked around it. (with the > help of an error message) > Without an error message you may had come to grief. > > Consider .............. > > Scenario: > For whatever reason -- you want to restore the /etc directory from a > local backup. > Lets just use a simple example.. > > "cp" should handle this. > "rsync" should also should handle this. > > But "cp" is your friend if you make an error ... "rsync" is not. > > OK .... There is NO source or destinantion directory "ets" but you make a > typo "ets" instead of "etc" > > "cp" will give you an error message whereas "rsync" will do what is not > intended and you will be *unaware* > > So the following commands > > [r...@localhost ~]# cp -a /backup/etc/* /ets > > [r...@localhost ~]# rsync -a /backup/etc/* /ets > > > "cp" will error out telling you that the target is not a directory if you use cp -ar /backup/etc /etc, cp, won't give you a warning. > whereas > "rsync will SILENTLY create the dir (ets) and populate it. so add a "-v" and you'll see some output telling you "created directory ets". This is not unusual. Most unix commands only bother you when there's a problem, and there was no problem here. Of course, you're going to ignore that output anyway, aren't you... > > So if you didn't check the result .... disaster beckons. So check it. > > Note that the creation of directories occur without a trailing slash on the > source. > But in that instance directory created is the name of the source directory. Note that blindly using *any* command, without paying attention, without understanding what you're doing, can lead to disaster. This is a PEBKAC, not a fault of the tool. > > > I have found some other gotchas ...... But do be aware of this (nasty) > feature. > Won't go into detail .... but some are ......... No, please do! > Like the deal with the trailing slash ..... which can cause issues --- > (often put there by bashs tab completion). > I like putting a "*" after a trailing slash as i find it more intuitive. > Also ........ creating a new dir once -- but not twice.. > Blah..Blah > > Cheers > Roger > -- > SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ > Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html > -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
