I hope that's an example of how not to do something because it doesn't work.
Code:
listpage="ls | more"
$listpage
ls: cannot access "|": no such file or directory
ls: cannot access "more": no such file or directory
The idea, I think, is to run the ls command to list the current directory, and feed its output into the more program so you can view it page by page. But you can't dump that text into a variable and expect it to work because the shell doesn't evaluate variables that way unless you force it to with eval.
Should I be concerned about the %runocc value be always 100. The CPU is 99% idle all the time and the paging is 0
MyMachine|10/23/2007 00:00:05|1.0|100||
MyMachine|10/23/2007 00:05:04|1.0|100||
MyMachine|10/23/2007 00:10:04|1.0|100||
MyMachine|10/23/2007 00:15:04|1.0|100||... (2 Replies)
Hi guys,
I have no idea on unix but suddenly, my cobol programs calls a unix script that i know nothing about.
can you guys interpret these lines for me?
i know its a print command but I want to actually know how many copies it prints.
qprt -da -P $1 -t '6' -i '6' -l '70' $2
qprt -da... (1 Reply)
Can someone help me out here. I can't get this piece of code to work. i.e. $ALL_EVENTS does not get interpreted in the if brackets. The first part is the code, the second part is the execution of the code. Note: $ALL_EVENTS does equal 2, but there is no value once passed to the if statement. ... (4 Replies)
Hi,
So I am new to Unix, and I need to check the performance of some apps I am running. But I don't know how to interpret the output from TOP.
Could somebody please explain the difference between the different values. And also explain how I can have a process which has a %CPU > 100?
... (7 Replies)
Was wondering if someone could interpret this for me -- I'm not sure what everything means. It's a shell script from my bash book:
cd ()
{
builtin cd "$@"
es=$?
echo "$OLDPWD ->$PWD"
return $es
}
what I don't quite understand is the "$@". I think, if I understand... (6 Replies)
I know $0 is the entire file's contents (at least I think that is what it is!), but what exactly is: $0!~
This was a snippet from a larger line
awk '$0!~/^$/ {print $0}'
This deletes blank lines, but I want to know specifically the $0!~ part... I am guessing /^$/ is regex for blank line...... (5 Replies)
hi All,
i have never used sed in Unix environment, but i have one script which is using this following command:
cat audit_session_rpt_MSP_20140331.lst|sed -n '/Apr 14/!p'| sed -n '/Page/!p'| sed -n '/UserName/!p' |\
egrep -v '^-|^=|^\*'|sed '/^$/d'|sed -e '1,7d'... (1 Reply)
I booted into single user mode with
/usr/sbin/reboot -- -s
but after doing a control -d
my
who -r
shows
run-level 3 Nov 17 14:07 3 0 S
I was expecting it to show run-level S
why is this still in run level 3?
thanks (1 Reply)
Discussion started by: goya
1 Replies
LEARN ABOUT OSX
universal::require
UNIVERSAL::require(3) User Contributed Perl Documentation UNIVERSAL::require(3)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 v5.16.2 2009-03-30 UNIVERSAL::require(3)