Category Archives: Computer Tip

Mount a Windows Shared Folder on Ubuntu 12.04 within VirtualBox

In today’s post, I will show you have to mount a Windows shared folder in Ubuntu 12.04 from within VirtualBox. A prerequisite is that you have to have VirtualBox Guest Additions already installed. If you haven’t done so and would like to know how, read this previous post where I show you how. Otherwise, continue reading and I’ll show you how to mount a shared folder.

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Regular Expression Cheatsheet

Here’s a quick cheatsheet of the metacharacters used in regular expressions.

.dotany one character
[ ... ]character classany character listed
[^...]negated character classany character not listed
^caretthe position at the start of the line
$dollarthe position at the end of the line
\<backslash less-thanthe position at the start of the word
\>backslash greater-thanthe position at the end of the word
|or, barmatches either expression it separates
( ... )parenthesesused to limit scope of |
?question markone allowed; none required ("one optional")
*asteriskunlimited allowed; none required ("any amount OK")
+plusunlimited allowed; one required ("at least one")
\1, \2, ...back referencematches text previously matched within first, second, etc., set of parentheses
\backslashescape a metacharacter to match literally
{ ... }bracesInterval; counting quantifier; specify number of matches

RS-232 PC Serial Port Pinout Conventions

At one point, the RS-232 9-pin Serial Port used to be a common connector on the back of every computer. But with USB being a much better protocol and easier to use, the serial port has just about disappeared from modern desktop computers. With servers, however, the serial port is still in use, but sometimes it’s only available as an IDC COM header connector on the motherboard. If you have a need for a serial port, then an IDC10-to-DB9 serial adapter might be required. I had just such a need recently and discovered that there are two industry standard pinout conventions in use, the AT/Everex and the DTK/Intel.  If you want to know more about how I discovered this and the differences, then continue reading.

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