This always throws me. I keep getting "permission denied" messages when
I simply try to rename files. Here's my code. The files in the directory
start out without an extension.
Dir.chdir("F:/images")
Dir.glob("*").each do |file|
File.new(file, "r").gets
if $_ =~ /%!PS-Adobe/
newfile = file + ".eps"
File.rename(file, newfile)
end
end
Thanks,
Peter
--
Posted via http://www.ruby-forum.com/.
Hi,
At Sun, 7 Oct 2007 11:15:04 +0900,
Peter Bailey wrote in [ruby-talk:272952]:
This always throws me. I keep getting "permission denied" messages when
I simply try to rename files. Here's my code. The files in the directory
start out without an extension.Dir.chdir("F:/images")
Maybe on Windows?
Dir.glob("*").each do |file|
File.new(file, "r").gets
This leaves the file still opened, and on Windows, it's
prohibited by the OS to move/rename files while they are
opened.
if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
File.rename(file, file + ".eps")
end
--
Nobu Nakada
Why would he need to open the file at all?
Dir.chdir("F:/images")
Dir.glob("*").each do |file|
if file =~ /%!PS-Adobe/
newfile = file + ".eps"
File.rename(file, newfile)
end
end
Regards,
Dan
On Oct 7, 12:07 am, Nobuyoshi Nakada <n...@ruby-lang.org> wrote:
Hi,
At Sun, 7 Oct 2007 11:15:04 +0900,
Peter Bailey wrote in [ruby-talk:272952]:> This always throws me. I keep getting "permission denied" messages when
> I simply try to rename files. Here's my code. The files in the directory
> start out without an extension.> Dir.chdir("F:/images")
Maybe on Windows?
> Dir.glob("*").each do |file|
> File.new(file, "r").getsThis leaves the file still opened, and on Windows, it's
prohibited by the OS to move/rename files while they are
opened.if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
File.rename(file, file + ".eps")
end
Nobuyoshi Nakada wrote:
Hi,
At Sun, 7 Oct 2007 11:15:04 +0900,
Peter Bailey wrote in [ruby-talk:272952]:This always throws me. I keep getting "permission denied" messages when
I simply try to rename files. Here's my code. The files in the directory
start out without an extension.Dir.chdir("F:/images")
Maybe on Windows?
Dir.glob("*").each do |file|
File.new(file, "r").getsThis leaves the file still opened, and on Windows, it's
prohibited by the OS to move/rename files while they are
opened.if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
File.rename(file, file + ".eps")
end
Yes, I'm on Windows. And, yes, it makes sense that it won't let me do it
because the file is, apparently, still open. But, I guess I'm stumped as
to how I can open the file to check that first line, match against that
first line, close the file, and then be able to rename the filename of
that particular file. Once the file is closed I really can't do anything
more inside that same if-end loop, can I?
-Peter
--
Posted via http://www.ruby-forum.com/\.
Daniel Berger wrote:
On Oct 7, 12:07 am, Nobuyoshi Nakada <n...@ruby-lang.org> wrote:
> if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
> File.rename(file, file + ".eps")
> endWhy would he need to open the file at all?
Because he's checking the first line of the file, not the filename.
--
Jabber: sepp2k@jabber.org
ICQ: 205544826
Peter Bailey wrote:
Nobuyoshi Nakada wrote:
if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
File.rename(file, file + ".eps")
endYes, I'm on Windows. And, yes, it makes sense that it won't let me do it
because the file is, apparently, still open. But, I guess I'm stumped as
to how I can open the file to check that first line, match against that
first line, close the file, and then be able to rename the filename of
that particular file. Once the file is closed I really can't do anything
more inside that same if-end loop, can I?-Peter
This line:
if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
opens the file, gets the first line, closes the file, and checks the
line against the regex for a match. If there is a match, this code
executes:
File.rename(file, file + ".eps")
end
That line renames the file.
But, I guess I'm stumped as
to how I can open the file to check that first line, match against that
first line, close the file, and then be able to rename the filename of
that particular file. Once the file is closed I really can't do anything
more inside that same if-end loop, can I?
What more do you want to do?
--
Posted via http://www.ruby-forum.com/\.
Oops, my mistake.
Regards,
Dan
On Oct 7, 7:30 am, Sebastian Hungerecker <sep...@googlemail.com> wrote:
Daniel Berger wrote:
> On Oct 7, 12:07 am, Nobuyoshi Nakada <n...@ruby-lang.org> wrote:
> > if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
> > File.rename(file, file + ".eps")
> > end> Why would he need to open the file at all?
Because he's checking the first line of the file, not the filename.
This line:
if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
opens the file, gets the first line, closes the file, and checks the
line against the regex for a match. If there is a match, this code
executes:File.rename(file, file + ".eps")
endThat line renames the file.
What more do you want to do?
I want to rename the file(s), and, that's what's not working. I'm
getting file permission errors.
--
Posted via http://www.ruby-forum.com/\.
Peter Bailey wrote:
> This line:
>>> if /%!PS-Adobe/ =~ IO.open(file) {|f| f.gets}
>
> opens the file, gets the first line, closes the file, and checks the
> line against the regex for a match. If there is a match, this code
>
> executes:
>>> File.rename(file, file + ".eps")
>>> end
>
> That line renames the file.
>
> What more do you want to do?I want to rename the file(s), and, that's what's not working. I'm
getting file permission errors.
The code posted above gives you permission errors? Or your original code gives
you permission errors? Because the code posted above really shouldn't. If the
code above gives you permission error, it's not because of open file handles.
Maybe you don't have permission to change the contents of the directory you
are working on?
--
Jabber: sepp2k@jabber.org
ICQ: 205544826
Actually, the code above should give him
TypeError: can't convert String into Integer
because IO.open wants an integer file descriptor 
He wants Kernel.open.
The working code is:
Dir.glob("*").each do |file|
if /%!PS-Adobe/ =~ open(file) {|f| f.gets}
File.rename(file, file + ".eps")
end
end
Peter, the key to Nobuyoshi's change above is that the rename now happens
*outside* the Kernel.open block. It doesn't matter that it happens inside
the if/end block; that's not what's holding the file open - Kernel.open is.
Now, the only thing that's done in the block is the gets, and the block is
closed on the very same line, before the rename happens.
On Mon, 8 Oct 2007 01:19:01 +0900, Sebastian Hungerecker wrote:
The code posted above gives you permission errors? Or your original code gives
you permission errors? Because the code posted above really shouldn't. If the
code above gives you permission error, it's not because of open file handles.
--
Jay Levitt |
Boston, MA | My character doesn't like it when they
Faster: jay at jay dot fm | cry or shout or hit.
http://www.jay.fm | - Kristoffer
Jay Levitt wrote:
The code posted above gives you permission errors? Or your original code gives
you permission errors? Because the code posted above really shouldn't. If the
code above gives you permission error, it's not because of open file handles.Actually, the code above should give him
TypeError: can't convert String into Integer
because IO.open wants an integer file descriptor
Kernel.open.The working code is:
Dir.glob("*").each do |file|
if /%!PS-Adobe/ =~ open(file) {|f| f.gets}
File.rename(file, file + ".eps")
end
endPeter, the key to Nobuyoshi's change above is that the rename now
happens
*outside* the Kernel.open block. It doesn't matter that it happens
inside
the if/end block; that's not what's holding the file open - Kernel.open
is.
Now, the only thing that's done in the block is the gets, and the block
is
closed on the very same line, before the rename happens.
Yes, Jay, that worked! And, I beg your pardon, Nobuyoshi, because, I
rather glibly just glanced over your code thinking you were just
repeating my code.
Now, I have to admit, I really need to look at your code, Jay, because,
to me, it's like a different "dialect." My primitive Ruby experience is
showing, I guess. I've certainly worked with blocks before, and I've
certainly worked with opening files before. And, I thought I was being
clever here by using "gets" for the first time, knowing that I only
wanted to read that first line. Previously, I've used File.read a lot,
but, I actually did want to read in the whole file then. But, your
casual use of a black and opening a file here kind of blows me away,
actually.
Thank you everyone.
Cheers,
Peter
On Mon, 8 Oct 2007 01:19:01 +0900, Sebastian Hungerecker wrote:
--
Posted via http://www.ruby-forum.com/\.
"casual use of a block" not "black." Sorry.
--
Posted via http://www.ruby-forum.com/.
Me too! I've only been doing Ruby for a few years, and then only for play
- just started being a pro-fessional this summer. Luckily, Ruby's so
natural, you'll be giving newsgroup advice yourself in just a few months.
The "block trick" happens to be one of the first Ruby idioms I read about.
In C++, people use RAII, Resource Acquisition Is Initialization, where you
wrap a resource in an object, "open" the resource by creating the object,
and "close" it by destroying the object.*
In Ruby, though, the object gets destroyed by garbage collection, not by
explicit destruction or stack unwinding. So RAII wouldn't work; you can
never guarantee when (or if) the resource will be closed. Instead,
resource-wrappers like File often let you specify a block; the wrapper
opens the resource, yields to the block, and closes the resource for you.
It's just a different wrapping idiom. If you haven't discovered
http://gotapi.com already, load up the Ruby tab and check out IO#open.
* Wasn't RAII originally called RAIN, Resource Acquisition Is
iNitialization? I could swear it was, and it certainly seems a more
memorable choice for an acronym, but Google's not bearing me out on this.
Then again, that was pre-Google. Anyone?
On Mon, 8 Oct 2007 07:40:42 +0900, Peter Bailey wrote:
Now, I have to admit, I really need to look at your code, Jay, because,
to me, it's like a different "dialect."
--
Jay Levitt |
Boston, MA | My character doesn't like it when they
Faster: jay at jay dot fm | cry or shout or hit.
http://www.jay.fm | - Kristoffer
Peter Bailey wrote:
Now, I have to admit, I really need to look at your code, Jay, because,
to me, it's like a different "dialect."
...
But, your
casual use of a black and opening a file here kind of blows me away,
actually.
1) First attempt at writing the code:
f = File.new(file)
line1 = f.gets
f.close
if /%!PS-Adobe/ =~ line1
File.rename(file, "#{file}.eps")
2) Hmmm...I think I can make those first three lines shorter. If I use
a File.open block that I read about in pickaxe, I won't have to call
close():
line1 = nil
File.open {|file| line1 = f.gets}
if /%!PS-Adobe/ =~ line1
File.rename(file, "#{file}.eps")
3) And, shorter still...:
line1 = File.open {|file| f.gets}
if /%!PS-Adobe/ =~ line1
File.rename(file, "#{file}.eps")
4) Hey, but look at 3). line1 appears on each line. So I can take what
line1 is equal to on the first line and substitute it's value in the
second line:
if /%!PS-Adobe/ =~ File.open {|file| f.gets}
File.rename(file, "#{file}.eps")
--
Posted via http://www.ruby-forum.com/\.
Jay Levitt wrote:
In Ruby, though, the object gets destroyed by garbage collection, not by
explicit destruction or stack unwinding. So RAII wouldn't work; you can
never guarantee when (or if) the resource will be closed. Instead,
resource-wrappers like File often let you specify a block; the wrapper
opens the resource, yields to the block, and closes the resource for you.
It's just a different wrapping idiom. If you haven't discovered
http://gotapi.com already, load up the Ruby tab and check out IO#open.
A FAQ on the C++ mailing list is "shouldn't C++ learn from Java and add a 'finally' keyword"?
Block closures teach us that both RAII and 'finally' are hacks, and the Execute Around Pattern is the Real Deal.
--
Phlip
In Ruby, though, the object gets destroyed by garbage collection, not by
explicit destruction or stack unwinding. So RAII wouldn't work; you can
never guarantee when (or if) the resource will be closed. Instead,
resource-wrappers like File often let you specify a block; the wrapper
opens the resource, yields to the block, and closes the resource for
you.
It's just a different wrapping idiom. If you haven't discovered
http://gotapi.com already, load up the Ruby tab and check out IO#open.* Wasn't RAII originally called RAIN, Resource Acquisition Is
iNitialization? I could swear it was, and it certainly seems a more
memorable choice for an acronym, but Google's not bearing me out on
this.
Then again, that was pre-Google. Anyone?
Well, I'd love to be able to give advice eventually in this forum, to
someone even newbier than me. It's such a generous forum that I feel I
have to give back in some way. . . .
--
Posted via http://www.ruby-forum.com/\.
* 7stud -- <dolgun@excite.com> (01:57) schrieb:
if /%!PS-Adobe/ =~ File.open {|file| f.gets}
File.rename(file, "#{file}.eps")
This is not C or Python, Ruby needs an end.
Or a one-liner:
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open {|file| f.gets}
mfg, simon .... l
I think that should be
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open(file){|
f> f.gets}
More terse:
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ IO.read(file,10)
On Oct 8, 12:09 pm, Simon Krahnke <overl...@gmx.li> wrote:
* 7stud -- <dol...@excite.com> (01:57) schrieb:
> if /%!PS-Adobe/ =~ File.open {|file| f.gets}
> File.rename(file, "#{file}.eps")This is not C or Python, Ruby needs an end.
Or a one-liner:
> File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open {|file| f.gets}
* William James <w_a_x_man@yahoo.com> (22:01) schrieb:
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open {|file| f.gets}
I think that should be
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open(file){|
f> f.gets}
Yeah, I correct one error and repeat another.
More terse:
File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ IO.read(file,10)
That's a violation of the DRY principle.
Define PS = '%!PS-Adobe' then
File.rename(file, "#{file}.eps") if IO.read(file, PS.length)[PS]
mfg, simon .... l
That's a violation of common sense. '%!PS-Adobe' isn't going
to change, and therefore 10 won't need changing. Unjustified
code inflation and a superfluous temporary variable.
Furthermore, why say ".length" when you can say ".size"?
You have a perverse, pronounced propensity for prolixity.
On Oct 8, 5:17 pm, Simon Krahnke <overl...@gmx.li> wrote:
* William James <w_a_x_...@yahoo.com> (22:01) schrieb:
>>> File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open {|file| f.gets}
> I think that should be
> File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ File.open(file){|
> f> f.gets}Yeah, I correct one error and repeat another.
> More terse:
> File.rename(file, "#{file}.eps") if /%!PS-Adobe/ =~ IO.read(file,10)
That's a violation of the DRY principle.
Define PS = '%!PS-Adobe' then
> File.rename(file, "#{file}.eps") if IO.read(file, PS.length)[PS]