"-e" and "-d" switches

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

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Re: "-e" and "-d" switches by dragonchild (Archbishop) on Mar 24, 2005 at 13:47 UTC
-d checks to see if something is a directory. -e checks to see if something exists. q.v. Filetest operators for more info. Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.	[reply]
Re: "-e" and "-d" switches by brian_d_foy (Abbot) on Mar 24, 2005 at 13:49 UTC
These are the file test operators (which are different from the command line switches that look the same). They're documented in perlfunc. In short, -d tests if its argument is a directory, and -e tests if its argument exists. In your code, it looks like the if() ensures that there is a true value for those hash keys and that the file or directory does not already exist. The next part probably creates them. -- brian d foy <bdfoy@cpan.org>	[reply]
Re: "-e" and "-d" switches by artist (Parson) on Mar 24, 2005 at 13:48 UTC
-d => If it is a directory -e => If it exists	[reply]
Re: "-e" and "-d" switches by manav (Scribe) on Mar 24, 2005 at 14:14 UTC
As an addendum, -d implies -e ,whereas -e does not imply -d Manav	[reply]
Re^2: "-e" and "-d" switches by dragonchild (Archbishop) on Mar 24, 2005 at 14:26 UTC
Not quite. A successful -d implies a successful -e. A failed -e implies a failed -d. However ... A failed -d says nothing about the success/failure of -e A successful -e says nothing about the success/failure of -d Being right, does not endow the right to be rude; politeness costs nothing. Being unknowing, is not the same as being stupid. Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence. Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.	[reply]
Re^3: "-e" and "-d" switches by nobull (Friar) on Mar 24, 2005 at 14:54 UTC
Manav wrote: -d implies -e -e does not imply -d dragonchild reasponded: Not quite. Actually in a formal logic sense your (dragonchild's) four statements are equivalent to manav's two. Or indeed the single statement: -d implies -e	[reply]
Re^4: "-e" and "-d" switches by dragonchild (Archbishop) on Mar 24, 2005 at 15:01 UTC
Re^4: "-e" and "-d" switches by RazorbladeBidet (Friar) on Mar 24, 2005 at 15:00 UTC
Re^5: "-e" and "-d" switches by dragonchild (Archbishop) on Mar 24, 2005 at 15:13 UTC
Re^4: "-e" and "-d" switches by manav (Scribe) on Mar 24, 2005 at 14:58 UTC
Re^3: "-e" and "-d" switches by manav (Scribe) on Mar 24, 2005 at 14:50 UTC
-d implies -e It was a positive implication. ! -e implies ! -d is negative implication. -e does not imply -d probably should have been -e does not necessarily imply -d Manav	[reply]
Re^2: "-e" and "-d" switches by mosh (Scribe) on Mar 24, 2005 at 14:21 UTC
Thanks Guys !!	[reply]
Re: "-e" and "-d" switches by ambs (Pilgrim) on Mar 25, 2005 at 18:34 UTC
The '-x' switches (perldoc -f -x) test various file properties. In your case, -d "filename" tests if "filename" is a directory. -e "filename" just checks if it exists. For example, -f "filename" will tell you if the file is a plainfile. You can use these switches to get other information from files like age or last change. Alberto Simões Python's syntax succeeds in combining the mistakes of Lisp and Fortran. I do not contrue that as progress. -- Larry Wall	[reply]