vnode

The vnode table represents all file activity in UNIX. There is a unique vnode allocated in the vnode table for each active file, each current directory, each mounted-on file, text file, and the root.  To see the number of vnodes available in Mac OS X, look to sysctl for the kern.maxvnodes variable using something similar to the following command: sysctl -A | grep vnode

Windows: Using SUBST to Map a Drive Letter to a Folder

So you’re using some old app, like FoxPro and it points to a drive letter.  You only have one disk but need to spoof or mimic that drive letter.  Well, subst to the rescue.  Basically, pick a letter.  Let’s say S: as it’s not currently in use.  Then use the subst command followed by the letter followed by the path to map a drive letter to it.  For example, if you want tot mount up c:/sales as S: then use this command: subst s: c:/sales Now, don’t misuse this command as a replacement for, let’s say net use.  If it’s a network path still map it using the net use command…

Regular Expressions

Basically, a regular expression is a pattern describing a certain amount of text. Their name comes from the mathematical theory on which they are based. But we will not dig into that. Since most people including myself are lazy to type, you will usually find the name abbreviated to regex or regexp. I prefer regex, because it is easy to pronounce the plural “regexes”. On this website, regular expressions are printed as regex. If your browser has proper support for cascading style sheets, the regex should be highlighted in red. This first example is actually a perfectly valid regex. It is the most basic pattern, simply matching the literal text regex. A “match” is the piece of text, or sequence of bytes or characters that pattern was found to correspond to by the regex processing software. Matches are highlighted in blue on this site. b[A-Z0-9._%+-]+@[A-Z0-9.-]+.[A-Z]{2,4}b is a more complex pattern. It describes a series of letters, digits, dots, underscores, percentage signs and hyphens, followed by an at sign, followed by another series of letters, digits and hyphens, finally followed by a single dot and between two and four letters. In other words: this pattern describes an email address. You can search through a text file to find email addresses, or verify if a given string looks like an email address. In this tutorial, I will use the term “string” to indicate the text that I am applying the regular expression to. I will highlight them in green. The term “string” or “character string” is used by programmers to indicate a sequence of characters. In practice, you can use regular expressions with whatever data you can access using the application or programming language you are working with.