You have a string that holds a (syntactically) valid path
to a file or folder on a Windows PC or network. If the path is a UNC
path, then you want to extract the name of the network server and the
share on the server that the path points to. For example, you want to
extract server
and share
from
\serversharefolderfile.ext
.
^\\([a-z0-9_.$●-]+)\([a-z0-9_.$●-]+)
Regex options: Case insensitive |
Regex flavors: .NET, Java, JavaScript, PCRE, Perl, Python, Ruby |
Extracting the network server and share from a string known to hold a valid path is easy, even if you don’t know whether the path is a UNC path. The path could be a relative path or use a drive letter.
UNC paths begin with two backslashes. Two consecutive backslashes are not allowed in Windows paths, except to begin a UNC path. Thus, if a known valid path begins with two backslashes, we know that the server and share name must follow.
The anchor ‹^
›
matches at the start of the string (Recipe 2.5). The fact that the caret also matches at
embedded line breaks in Ruby doesn’t matter, because valid Windows paths
don’t include line breaks. ‹\\
› matches two literal backslashes. Since the
backslash is a metacharacter in regular expressions, we have to escape a
backslash with another backslash if we want to match it as a literal
character. The first character class, ‹[a-z0-9_.$●-]+
›, matches the name of the network
server. The second one, after another literal backslash, matches the
name of the share. We place both character classes between a pair of
parentheses, which form a capturing group. That way you can get the
server name alone from the first capturing group, and the share name
alone from the second capturing group. The overall regex match will be
\servershare
.
Recipe 2.9 tells you all about capturing groups.
See Recipe 3.9 to learn how to retrieve text matched by capturing groups in your favorite programming language.
Follow Recipe 8.19 if you don’t know in advance that your string holds a valid Windows path.