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If you require more control of your file permissions, Access Control Lists (ACLs) may be the way to go. ACLs go beyond the normal user/group/other paradigm and allow setting permissions per individual user or group. ACLs are a great option when you want to grant permissions without creating entire user groups. They are also great when you need to allow your non-super-users the ability to set permissions. You still have to be the main owner of a file to modify its permissions, though. Proceed with caution! ACLs can cause mysterious permission errors that are not immediately obvious to someone who isn't aware of them. For this very reason, ACLs are enabled but not used by default in the latest RHEL / CentOS. To check if your ext3 filesystem has the proper default options, use tune2fs. Look for "Default mount options:" with acl set. Let's assume we have /dev/sdb1 mounted on /data1 and we want to enable the acl option. [root@foobaz ~]# tune2fs -l /d...

Explain Linux / UNIX TCP Wrappers / Find Out If Program Compiled With TCP Wrappers W hat are TCP Wrappers? How do I find out if program / server / service is compile with TCP Wrappers? What are the advantages and disadvantages of TCP Wrappers over Firewalls like netfilter or pf? How do I protect my Mac OS X or Sun Solaris or Linux workstation using TCP Wrappers? Almost all BSD / UNIX / Linux like operating systems are compiled with TCP Wrappers support. For e.g. Solaris 9, various Linux / *BSD distributions, and Mac OS X have TCP Wrappers configured to run out-of-the-box. It is a library which provides simple access control and standardized logging for supported applications which accept connections over a network. TCP Wrapper is a host-based Networking ACL system, used to filter network access to Internet. TCP wrappers was original written to monitor and stop cracking activities on the UNIX workstation in 90s. It was best solution in 90s to protect the UNIX work...

How To Get System Info In Linux Here's a list of commands, tips and info that I've compiled from several different sources. I use this as a quick reference when I need to find info about my computer or my operating system. General System Info Note: Most hardware info commands should be run as root. Some even show more info when run as root. Run qtparted or GParted for hard drive and partition info!!! Also, see KDiskFree . And fdisk -l for info on all partitions. hardinfo - good report to run; also, check the Details tab. Ko's Method For Getting A Hardware Report: This report runs a series of reports, some of which are listed individually further on in this document. Install through Synaptic the package installation-report . Then run in a maximized konsole: report-hw or report-hw > hwreport (Sends the output to a textfile called hwreport in your home folder) sysinfo a nice graphical display, run it from a terminal. hal-device-manager kde-hal-dev...

Linux: How To Create Multiple Users Accounts in Batch The useradd command is used to create a new user or update default new user information from the command line. However, sometimes you need to create a large number of users or import usernames from a text file. You can use newusers command, which update and create new users in batch. This is useful at universities or large corporate Linux networks. Adding users in batch saves the time. Task: Set Password Type the following command to change or set user password: echo "username:password" | newusers For example, change user password for vivek user: echo "Vishvendra:Password" | newusers Task: Update and create new users in batch newusers command reads a file of user name and clear-text password pairs and uses this information to update a group of existing users or to create new users. Each line is in the same format as the standard password file. This command is intended to be used in a large syst...