Can someone explain the difference between backticks and system when
evaluated in these if statements:
sub getDate {
print "start date\n";
if ( system("/bin/date") ) {
print "can't get date\n";
exit(2);
}
print "finish date\n";
}
Returns the following:
start date
Thu... (5 Replies)
Sorry to be a pain, but how does the else work in the if statements?
Ive been making scripts with if statements but i cant get the else statements working.
Can you help? (8 Replies)
I had different problem scenarios with IF statement. Can any expert please enlighten me on the difference with these scenarios. Thank you.
1st Scenario:
testdate=`date +%Y%m`
test=`cat /var/log/database0.$testdate*.log | grep "Errors found during processing" | tail -10`
if
then
... (4 Replies)
hi friends.
yo i have a textfile with urlīs in it
sometimes middle in text, sometimes one url alone is a line
i append a string right behind the domain name
so that http://unix.com becomes http://unix.com.APPENDTHIS on all occasions.
i use this sed-line to achieve this:
sed -i... (3 Replies)
I have a laptop running Ubuntu Gusty. I have recently used applications such as AWN, Emerald, etc... to create a Mac OS X Leopard like environment. It works almost perfectly except for one little glitch. When I open most of my apps/windows, they all open with the top bar(with includes close,... (5 Replies)
Hello All,
I am trying to clone an entire AIX virtual machine to a new virtual machine including all partitions and OS.Can anyone help me on the procedure to follow? I am not really sure on how it can be done.Thanks in advance.
Please use CODE tags for sample input, sample output, and for code... (4 Replies)
Hi
Please dont consider this as duplicated post..
I am using below pattern to find delete files to bringdown disc size.. however how i can make sure ist going to correct folder and searching for files... while print "echo rm " LastFile correctly print files names for deletion, but when i... (7 Replies)
Discussion started by: onenessboy
7 Replies
LEARN ABOUT DEBIAN
universal::require
UNIVERSAL::require(3pm) User Contributed Perl Documentation UNIVERSAL::require(3pm)NAME
UNIVERSAL::require - require() modules from a variable
SYNOPSIS
# This only needs to be said once in your program.
require UNIVERSAL::require;
# Same as "require Some::Module"
my $module = 'Some::Module';
$module->require or die $@;
# Same as "use Some::Module"
BEGIN { $module->use or die $@ }
DESCRIPTION
If you've ever had to do this...
eval "require $module";
to get around the bareword caveats on require(), this module is for you. It creates a universal require() class method that will work with
every Perl module and its secure. So instead of doing some arcane eval() work, you can do this:
$module->require;
It doesn't save you much typing, but it'll make alot more sense to someone who's not a ninth level Perl acolyte.
Methods
require
my $return_val = $module->require or die $@;
my $return_val = $module->require($version) or die $@;
This works exactly like Perl's require, except without the bareword restriction, and it doesn't die. Since require() is placed in the
UNIVERSAL namespace, it will work on any module. You just have to use UNIVERSAL::require somewhere in your code.
Should the module require fail, or not be a high enough $version, it will simply return false and not die. The error will be in $@ as well
as $UNIVERSAL::require::ERROR.
$module->require or die $@;
use
my $require_return = $module->use or die $@;
my $require_return = $module->use(@imports) or die $@;
Like "UNIVERSAL::require", this allows you to "use" a $module without having to eval to work around the bareword requirement. It returns
the same as require.
Should either the require or the import fail it will return false. The error will be in $@.
If possible, call this inside a BEGIN block to emulate a normal "use" as closely as possible.
BEGIN { $module->use }
SECURITY NOTES
UNIVERSAL::require makes use of "eval STRING". In previous versions of UNIVERSAL::require it was discovered that one could craft a class
name which would result in code being executed. This hole has been closed. The only variables now exposed to "eval STRING" are the
caller's package, filename and line which are not tainted.
UNIVERSAL::require is taint clean.
COPYRIGHT
Copyright 2001, 2005 by Michael G Schwern <schwern@pobox.com>.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
See http://www.perl.com/perl/misc/Artistic.html
AUTHOR
Michael G Schwern <schwern@pobox.com>
SEE ALSO
Module::Load, "require" in perlfunc, <http://dev.perl.org/rfc/253.pod>
perl v5.10.0 2009-03-30 UNIVERSAL::require(3pm)