The commands work fine, and one understands pretty easily while playing
with them how the stack works.
There are just ambiguities in the manual.
Check the pushd builtin command documentation.
"
`pushd'
pushd [-n] [+N | -N | DIR]
Save the current directory on the top of the directory stack and
then `cd' to DIR. With no arguments, `pushd' exchanges the top
two directories.
"
The first sentence implies that the current directory is not part of what
the manual calls the "directory stack". The current directory is pushed on
the stack and then the command cds to DIR (which will not be part of the
stack).
The second sentence says that the top two directories are exchanged with no
arguments, but in practice it's the current dir and the top stack directory
that are exchanged if we accept what they define as stack in the first
sentence. In that perspective, the second sentence should be rewritten
something like : "With no arguments, pushd exchanges the top stack
directory with the current directory and cds to the old top directory".
It's details, but I think the manual should state whether the stack
includes the cd and correct those little ambiguities. What does it refer to
when it uses terms like "top directory of the stack".. Is is the current
dir or the last pushed directory ?
2015-08-16 13:51 GMT+02:00 Chet Ramey <chet.ra...@case.edu>:
> On 8/14/15 6:08 AM, Tim Nielens wrote:
>
> > Bash Version: 4.3
> > Patch Level: 39
> > Release Status: release
> >
> > Description:
> > There is a ambiguity about the directory stack in the manual: 6.8.1
> > Directory Stack Builtins
> >
> > It's difficult to understand if the current directory is part of the
> stack
> > or not.
>
> `dirs' always displays the directory stack, and the current directory is
> always the first element (sometimes the only one).
>
> The current directory is always the implicit top of the directory stack,
> so things like popd and pushd without arguments can use it, so `dirs' lists
> it as the first element.
>
> When you use pushd for the first time, for instance, you push the directory
> given as an argument `on top' of the current directory, and make it the
> new current directory, so it's the top of the stack for a subsequent pushd
> or popd.
>
> If you haven't pushed anything, there's nothing to pop, and `popd' returns
> an error message. If you have pushed something, you pop the current
> directory and return to the immediately previous one.
>
> pushd always changes the current directory unless the -n option is given.
> Since the `topmost' element of the stack is always the current directory,
> popd will change the current directory if it operates on the top element
> (popd, popd +0), unless the -n option is given.
>
> Since a successful `pushd' or `popd' always prints the contents of the
> directory stack, there should not be too much confusion about its members.
>
> --
> ``The lyf so short, the craft so long to lerne.'' - Chaucer
> ``Ars longa, vita brevis'' - Hippocrates
> Chet Ramey, ITS, CWRU c...@case.edu
> http://cnswww.cns.cwru.edu/~chet/
>
