Oracle Tutoring, Campbell River, BC
(250) 203-6544 (text) or (250) 830-0295 (talk)
I’ve been using a directory structure in a new context that doesn’t seem to recognize relative paths. For instance, let’s imagine the directory structure
From dir3, the link
./the_file.txt
used to lead to the_file.txt. Yet now, it doesn’t.
So now, /dir0/dir3/the_file.txt is needed to access the_file.txt in dir3.
HTH:)
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.A useful feature of regular expressions is the optional use of parentheses. There are numerous reasons to use them, but one is to report parts of the match.
Consider the following:
if($strng=~m/(hehe(_[\d]+_)([\d]+d)(-[d]+))/i){
print “$1\n$2\n$3\n$4\n”;
}
else{
print “no match”;
}
The output would be (assuming no typos:)
$1 denotes the contents of the first set of parentheses in the matching pattern, $2 the second, and so on. The groupings can be used to organize the output from the match.
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Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.The bell character is ASCII 7; its symbol is BEL.
Notepad++ allows BEL to be inserted in a text file: from the Edit menu, click Character Panel. An insertion panel appears at right: on it, you can double-click ASCII 7 for BEL, or whatever other ASCII character might be needed:)
Source:
ascii.cl/control-characters.htm
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.In my post from Aug 15 I mention the Perl feature say and that, to enable it, a user might key
use v5.10;
below the she-bang line. (Apparently, a version past 5.10 may also suffice.)
I’ve read since that the line
use feature ‘say’;
also enables the use of say.
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Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.I’ve never known of say, but I tried it on a console and indeed, it works. I needed to include use v5.10; for say to work. I understand, however, that the version can be higher.
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Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.From a practical point of view, port forwarding is a way to set up a router so that outside inquiries can reach a resource behind it, in the internal network.
Port forwarding relies on a two-part construct:
(See yesterday’s post for an explanation of what a port is.)
Typically, a router will block unsolicited traffic from accessing computers behind it, which is its firewall function.
Let’s imagine the application you want to enable outside users to access is reached via port x0y0 on local device D0. The port forward that will enable such access:
Router, when a request for port x0y0 arrives, send it along to D0, port x0y0.
Now, outside clients can reach that inner device D0, through the firewall and past the router, by virtue of their request for port x0y0. The setup is called port forwarding.
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Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.A port can be physical or logical. A physical port is a plug-in socket at which to attach a device to the computer, such as a printer. USB ports comprise an example.
A logical port, such as port 80, designates the program a request desires to connect through. Port 80 means http activity. The logical ports on a computer are 0 to 65535.
Source:
searchnetworking.techtarget.com
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.viewed unfavourably, viewed with disapproval.
In computer science, certain ways of writing code can become deprecated after newer, preferred ways supplant them. The deprecated code may continue to be supported for a time, but after being labelled “deprecated”, it’s vulnerable to sudden dysfunction.
Source:
Gilmour, Lorna (ed). Collins Essential Canadian English Dictionary & Thesaurus. Glasgow: HarperCollins, 2006.
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.
For background, my post from April 2, as well as my post from yesterday, connect with today’s topic.
Switches can be used in a variety of ways, so a simple conception only explains one application. However, I find this idea helpful:
Imagine a self-contained local network of computers physically connected. A given member can send a message to a specific other, or to all others at once. Then, the simplest central connection among these computers is a switch.
A switch is different from a hub (once again, my post from yesterday) in that the switch can forward a message to a specific intended recipient, whereas the hub just forwards it to everyone.
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Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.
Source:
Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.