or operator not working at checking directories

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

First of all can someone tell me why this doesnt work and give me a working expample :)

  ### Url has to start with
  if ($homeurl !~ m[^http:\/\/] or m[^https:\/\/]) {
      &inerror("Your home url has to start with http:// or https://");
  }
[download]

... also
well how could I get this to work

if(-d "directory") {
}
[download]

how could I do something like

if(-d -r -w -x -R -W -X "directory") {
}
[download]

*hint - im trying to see if the directory is CHMOD to 777

Comment on or operator not working at checking directories Select or Download Code

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Re: or operator not working at checking directories by epoptai (Curate) on Jun 30, 2002 at 04:27 UTC
It doesn't work because the match after the or is not happening. You need to be more explict about the second match and use and instead: `if ($homeurl !~ m[^http://] and $homeurl !~ m[^https://]) { print "Your home url has to start with http:// or https://"; }` [download] Or you could put the or inside the match (using \| which means 'or'): `if ($homeurl !~ m[^http://\|https://]) { print "Your home url has to start with http:// or https://"; }` [download] Or you could use a ? after the s to signify that it may or may not exist, the most elegant method in this case: `if ($homeurl !~ m[^https?://]) { &inerror("Your home url has to start with http:// or https://"); }` [download] To find out the permissions on a file or directory check out stat. -- Check out my Perlmonks Related Scripts like framechat, reputer, and xNN.	[reply] [d/l] [select]
Re^2: or operator not working at checking directories by Aristotle (Chancellor) on Jun 30, 2002 at 10:42 UTC
`if ($homeurl !~ m[^http://\|https://]) {` Careful. Your regex tests for `http://` at the start of the string, or `https://` anywhere in the string. The \|-alternative is greedy if not enclosed in brackets. Also, it is better to keep `or` distinctions like this outside the regex engine. In reply to the original question, I would suggest that it's semantically much better to write this as: `unless ($homeurl =~ m[^http://] or $homeurl =~ m[^https://]) { &inerror("Your home url has to start with http:// or https://"); }` [download] which to me feels like it more clearly conveys what's meant here. Finally, though, I want to suggest, in this specific instance, to use the `?` quantifier: `unless ($homeurl =~ m[^https?://]) { &inerror("Your home url has to start with http:// or https://"); }` [download] `____________` Makeshifts last the longest.	[reply] [d/l] [select]
Re: or operator not working at checking directories by dws (Chancellor) on Jun 30, 2002 at 04:34 UTC
how could I do something like if(-d -r -w -x -R -W -X "directory") { See perlfunc. There's an example of how to do this at the bottom of the section that describes the -X functions. (Hint: pay close attention when you see _ described.)	[reply]


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