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In storage environment, the file system reliability is almost a common issue. As for my understanding, when a ext3 file system is under use, its integrity is keeping broken day by day, as most of the threaded applicatons cannot take fully control of data blocks. After a long time running, fsck becomes [...]

Symbolic linked files are commonly used in Linux system. For example some service inital scripts are stored in /etc/init.d and linked to /etc/rc0.d, /etc/rc1.d, /etc/rc2.d, /etc/rc3.d, /etc/rc4.d, /etc/rc5.d and /etc/rc6.d, so that the system is able to control related services in different runlevel. (function(d, [...]

The mod_setenvif module allows you to set environment variables according to whether different aspects of the request match regular expressions you specify. These environment variables can be used by other parts of the server to make decisions about actions to be taken. The SetEnvIf directive defines [...]

The stat command can be use to check file status ( like file properties on Windows platform) or check the file system status on Linux. It comes from GNU Coreutils package. (function(d, s, id) { var js, fjs = d.getElementsByTagName(s)[0]; if (d.getElementById(id)) return; js = d.createElement(s); [...]

This is a Perl module that was posted in a comment by our friend Justy (a.k.a. the iSheep), it solves a problem that I’ve faced a lot, especially with Perl scripts that run as daemons, where you need to copy files to a mount point. but if the mount point has failed then you’re just copying the files [...]

What is a VLAN A VLAN is a virtual LAN, it is a broadcast domain created by switches. Normally, it is a router creating that broadcast domain. With VLAN’s, a switch can create the broadcast domain. This works by, you, the administrator, putting some switch ports in a VLAN other than 1, the default [...]

This is a simple python script  based on some former rwhois code. It shows us an easy way on how to get detailed information about a specific IP address: joseph@e54:~$ python ip-whois.py 94.75.214.11 ====== whois.arin.net OrgName: RIPE Network Coordination Centre OrgID: [...]

In virtualized environment, we sometimes need to generate MAC address for each virtual machine at the time of creation. Since is a nearly unlimited amount of numbers on the same subnet, it is almost impossible that we would get the same MAC address. In the follwing paragraph, we’ll show you how [...]

Suppose that we have a hash like this: my %thehash = ( "abc" => {'a', 'office', '123'}, "cax" => {'s', 'domain', '254'}, "adm" => {'s', 'atwork', '254'}, "tec" => {'s', 'domain', '294'}, "ued" => {'s', 'domain', '254'} ); (function(d, s, id) { var js, fjs = d.getElementsByTagName(s)[0]; [...]

As we know there’s a kind of read-only variables in bash in common linux system, typically $BASH_COMPLETION and $BASH_COMPLETION_DIR are both readonly variables. This post will focus on the following two topics, how can we set readonly variables in Bash, and how can we unset them. (function(d, [...]