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From: Sven Mascheck on 30 Jun 2010 10:16 Janis Papanagnou wrote: > Curious; are there systems where /usr/bin and /bin are not equivalent > (or even identical [by one directory linking the other])? You can find that specific info for some unix flavours hidden in a collection of real world shell versions/paths. (However, the actual contents of the respective directories and a detailed overview about various Linux Distributions are not present.) http://www.in-ulm.de/~mascheck/various/shells/ It's the first item in a respective flavour. In short: - a symbolic link from /bin to /usr/bin is a convention on most commercial unix flavours after the historic days (exceptions are e.g. OpenServer and Unicos). - it's a rare exception on free unix flavours
From: Wayne on 30 Jun 2010 15:18 On 6/30/2010 9:14 AM, Janis Papanagnou wrote: > Chris F.A. Johnson schrieb: >> On 2010-06-30, Janis Papanagnou wrote: >>> Seebs schrieb: >>>> [...] >>>> More generally, the same pattern applies to any other bin directory; if >>>> you have a bin directory that's specific to a working project, or a personal >>>> bin directory, it's put in front of /usr/local, which is in turn in front >>>> of plain /usr/bin and /bin, [...] >>> Curious; are there systems where /usr/bin and /bin are not equivalent >>> (or even identical [by one directory linking the other])? >>> >>> I don't recall having worked on a Unix system with different contents >>> in those two directories. >> >> The only systems where I've seen them equivalent is Sun/Solaris; on >> all others they are separate directories with different commands. >> > > I am specifically interested in AIX 3/4 and HP-UX 9/10 which have > been just two Unix families where I worked some decade(s) ago but > have no access currently. Also those Suse Linux'es (version 7, or > earlier). (I really thought to have seen that in several places, > and I was confident that at least AIX had that too. It's certainly > also possible that I may be misremembering, though.) > > And what's the difference between the contents of /usr/bin and /bin > (ignoring /usr/sbin and /sbin for the moment) on those system where > it differs? > > Janis For Linux, see <http://www.pathname.com/fhs/pub/fhs-2.3.html> or the man page for hier(7). For Solaris, see the man page for filesystem(5). No doubt there is a similar man page for AIX and other systems. -- Wayne
From: John Kelly on 30 Jun 2010 16:59 On Wed, 30 Jun 2010 14:10:43 +0200, Janis Papanagnou <janis_papanagnou(a)hotmail.com> wrote: >Curious; are there systems where /usr/bin and /bin are not equivalent >(or even identical [by one directory linking the other])? Linux has common system utilities, like sed, in /bin >fw:~# ls -l /bin/sed >-rwxr-xr-x 1 root root 40468 2008-03-02 22:22 /bin/sed >fw:~# ls -l /usr/bin/sed >ls: cannot access /usr/bin/sed: No such file or directory Putting /usr/bin ahead of /bin in your path, causes an extra path search every time you invoke sed, or any other common utility. That's why I use a default path of: /bin:/usr/bin And by extension, the same applies to /usr/local/bin; having it at the front of your path means needless path searches for system utilities. So for efficiency, I prefer: /bin:/usr/bin:/usr/local/bin And if I ever need to override standard system binaries; I will put /opt/local/bin at the front of my default path, though at the undesirable cost of extra path searches, which so far, I have avoided. Using /opt/local/bin for this purpose does not conflict with FHS 2.3; it merely extends the use of /opt in a way not addressed by the FHS. OTOH, if some clown decides to name his package "local" I wouldn't install his silly nonsense anyway. So why would I care. -- Web mail, POP3, and SMTP http://www.beewyz.com/freeaccounts.php
From: Janis Papanagnou on 30 Jun 2010 17:37 On 30/06/10 22:59, John Kelly wrote: > [...] > > Putting /usr/bin ahead of /bin in your path, causes an extra path search > every time you invoke sed, or any other common utility. Shouldn't that be covered by cashing ("hashing", "tracked alias")? I.e., without sacrificing the path precedence (overriding) feature. Janis [...]
From: Janis Papanagnou on 30 Jun 2010 17:40
On 30/06/10 16:16, Sven Mascheck wrote: > Janis Papanagnou wrote: > >> Curious; are there systems where /usr/bin and /bin are not equivalent >> (or even identical [by one directory linking the other])? > > You can find that specific info for some unix flavours hidden > in a collection of real world shell versions/paths. > (However, the actual contents of the respective directories and > a detailed overview about various Linux Distributions are not present.) > > http://www.in-ulm.de/~mascheck/various/shells/ > > It's the first item in a respective flavour. In short: > - a symbolic link from /bin to /usr/bin is a convention on most > commercial unix flavours after the historic days (exceptions are > e.g. OpenServer and Unicos). Am I reading that correctly; that you confirm my memories for those commercial Unix systems (AIX, HP-UX, and SunOS) that I worked on? > - it's a rare exception on free unix flavours Cygwin is probably no good example, but there you have equal /bin and /usr/bin contents as well. Janis |