Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Trim a string using Perl
Answer:
To trim a string in Perl, use the following subroutine - trim():
#!/usr/bin/perl
use strict;
sub trim($) {
my $string = shift;
$string =~ s/^\s+//;
$string =~ s/\s+$//;
return $string;
}
print trim (' foo ');
Rename file in Linux
Answer
The easiest way to rename a file in Linux is to move the file, using the mv command.
e.g.
# mv old_file.txt new_file.txt
Making ntp works in Xen domU
Answer:
In Xen, the clocks of all VMs are controlled by dom0, in order to make ntp work independently, you can edit the file "/etc/sysctl.conf"
xen.independent_wallclock = 1
Restart your server to take effects.
What is the difference between include() and require() in PHP?
Answer:
From the PHP's document
require() is identical to include() except upon failure it will also produce a fatal E_ERROR level error. In other words, it will halt the script whereas include() only emits a warning (E_WARNING) which allows the script to continue.
Print the last executed command begin with a specific letter
To print the last executed command begin with a specific letter, e.g.
# date
Thu Mar 18 21:55:55 HKT 2007
!d:p
date
The key is the :p modifier
