Underline the current line in vim
Answer:
Underline the current editing line in vim is very useful, to do so, follow the guide below.
1. Press [ESC] to get into command mode
2. Enter :set cursorline
Nov 192010
Linux Ask!
Nov 182010
Is PHP pass by reference or pass by value?
Answer:
PHP is pass by value, see the code below:
<?php
class Dog {
public $name;
public function __construct($name) {
$this->name = $name;
}
}
function bar($dog) {
$dog = new Dog("bar");
echo $dog->name;
}
$d = new Dog("foo");
echo $d->name;
bar($d);
echo $d->name;
If PHP is pass by reference, the last echo statement will print out "bar" instead of "foo", which is not true.
Nov 172010
Change user's timezone setting
Answer:
User can have their own timezone setting.
1. Firstly, you need to find out the timezone string by selecting interactively using the command tzselect command.
2. Append the string to the file ~/.profile
E.g.
# echo " TZ='Asia/Hong_Kong'; export TZ" >> ~/.profile
Nov 162010
Enable compression during scp transfer
Answer:
When you transfer files which are mainly text based using scp command, it is always good to compress them to save the bandwidth needed.
To do so:
# scp -C test.txt john@remoteserver:/home/john/
Nov 152010
What is the difference between || and or in Perl?
Answer:
In Perl, sometimes you can use both `||` and `or` to to do the same thing. But the main different is:
- or has very low precedence, which is useful for flow control
Example:
open FILE, $file or die("Cannot open $file"); # Work
open FILE, $file || die("Cannot open $file"); # Does not work , because it it same as the next statement
open FILE, ($file || die("Cannot open $file")); # Obviously not work
