directory exists

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

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Re: directory exists by Zaxo (Archbishop) on Jun 03, 2005 at 00:05 UTC
What you have should tell you if something called /mydir is in the root fs. To see if it is a directory call -d. `my $mydir = '/mydir'; if ( -e $mydir and -d _ ) { print $mydir, ' directory exists.', $/; }` [download] The underscore handle makes -d use the cached stat call from -e. After Compline, Zaxo	[reply] [d/l]
Re^2: directory exists by ikegami (Patriarch) on Jun 03, 2005 at 02:50 UTC
Isn't testing for -e and -d redundant? -d includes a -e test.	[reply]
Re^3: directory exists by Fletch (Bishop) on Jun 03, 2005 at 02:53 UTC
Yup. Underneath it calls `stat(2)`, which would return `ENOENT` if it doesn't exist (file or directory). `-d` goes on to use the returned `struct stat*` to check if it's a directory or not. -- We're looking for people in ATL	[reply] [d/l]
Re^3: directory exists by Zaxo (Archbishop) on Jun 03, 2005 at 03:19 UTC
Yes. I'd use a test like this in real code, and I guess it got into my recommendation: `is_dir { -e shift() ? -d _ ? 1 : 0 : undef; }` [download] With that I can test truth to see if there is a directory of that name, or defined to see if the name is in use. After Compline, Zaxo	[reply] [d/l]
Re^4: directory exists by ambrus (Abbot) on Jun 03, 2005 at 19:01 UTC
Re^2: directory exists by Anonymous Monk on Jun 03, 2005 at 00:26 UTC
Hello, thank u for the very fast reply. I tried the syntax you posted but it doesnt work for me ..for some reason. my $dev = '/dev'; if (-e $dev && -d _) { # print "Directory exists \n"; print $dev, ' directory exists.', $/; } but If I use perl -wle '$x=q(/dev); print "OK" if -d $x' , it works fine from the command line	[reply]
Re^3: directory exists by Zaxo (Archbishop) on Jun 03, 2005 at 00:47 UTC
It works for me, do you have shell quoting problems? `$ perl -e'my $dev = "/dev";if (-e $dev and -d _) {print $dev," directo +ry exists.",$/}' /dev directory exists. $` [download] After Compline, Zaxo	[reply] [d/l]
Re^3: directory exists by tlm (Prior) on Jun 03, 2005 at 00:46 UTC
You may be "suffering from buffering." Try switching off output buffering by adding the line `$\| = 1` somewhere before the `print` statement. the lowliest monk	[reply]
Re^3: directory exists by ambrus (Abbot) on Jun 03, 2005 at 19:09 UTC
Dear anonymous monk. It would be wise if you used code tags when entering multi-line code like the one above, because this way it's not clear where the end of the comment is.	[reply]
Re^3: directory exists by Anonymous Monk on Jun 06, 2005 at 02:55 UTC
Hello everyone, THANK YOU FOR ALL YOUR REPLIES...THE SYNTAX YOU SUGGESTED WORKED ONCE I CHANGED A FEW LINES OF CODE IN ANOTHER PLACE..... thank you very much	[reply]
Re^2: directory exists by Anonymous Monk on Jun 03, 2005 at 00:43 UTC
Hello, thank u for the very fast reply. I tried the syntax you posted but it doesnt work for me ..for some reason. my $dev = '/dev'; if (-e $dev && -d _) { print $dev, ' directory exists.', $/; } but If I use perl -wle '$x=q(/dev); print "OK" if -d $x' , it works fine from the command line	[reply]
Re: directory exists by tlm (Prior) on Jun 03, 2005 at 00:06 UTC
I'm surprised it doesn't work (assuming, of course that `/mydir` indeed exists). Is this a Unix system? Incidentally, I would use the `-d` test in this case, which implies `-e`, and returns true only if the tested file not only exists, but is actually a directory. For example (OS: Linux): `% perl -wle '$x=q(/boot); print "OK" if -d $x' OK` [download] the lowliest monk	[reply] [d/l]
Re^2: directory exists by Anonymous Monk on Jun 03, 2005 at 00:40 UTC
This is a unix system	[reply]
Re: directory exists by jweed (Chaplain) on Jun 03, 2005 at 00:08 UTC
What is your expected behavior? It seems to work for me, though I would make the condition: `... if (-e $mydir && -d _){ ...` [download] to explicitly test that the file is a directory. Code is (almost) always untested. http://www.justicepoetic.net/	[reply] [d/l]