[nflug] Understanding Linux File

robert at wolfe-n-wolfe-enterprises.com robert at wolfe-n-wolfe-enterprises.com
Sun Sep 16 04:47:28 EDT 2007

Saw this is in one of the Linux message bases here on my BBS and thought I
would share it with everyone: 
**This message was originally sent from TIME WARRIOR 
and was forwarded to you by Robert Wolfe 
Alexandre Vassalotti 
Understanding Linux File Permissions 
January 2, 2007 at 3:35 pm + Filed under Tutorials, Linux 
File permissions are probably one of the biggest difference between Windows  
and Unix-style operating systems. They make Linux much more secure when they  
are well used. However, they can also cause nightmare to the casual Linux  
The first thing you need to know is that a Linux system has two way of  
classifying users. There is, of course, the user name, but there is also  
groups. Groups are, strictly speaking, only a way to share permissions between  
the users. For example, all the member of the admin group on your system is  
able to use the command sudo. As you probably know, sudo allows you to run a  
command as another user (by default, the root user). 
Let me introduce you to your command-line friends that will help you to manage  
the permissions of your system. 
    * adduser: This command let you add new user on your system. It can also  
add a user into a group. 
    * addgroup: Its name says it all. This command let you add new group on  
your system. 
    * chmod: I believe this is the most widely known Unix command. It is even  
a verb in the world of server-side technology, like PHP. This command let you  
alter the permissions of a file. It is a swiss-army knife. Learn it, and use  
it well. 
    * chown: Also a very important command, chown can change the user and  
group ownership of a file. 
    * chgrp: This is chown’s little brother. Unlike chown, this command can  
only change the group ownership of a file. 
    * groups: Somehow less important but still useful, groups shows you the  
groups you are a member of. 
    * whoami: Don’t know why, but I love the name of this command. Anyway,  
this command tells you who you are. 
    * who: This command shows you who is login on your system. I never use it,  
since I find w more useful for my usage. 
    * w: And here our last little friend, the w command. It displays a list of  
the logged users like who, but also display their attached process and the  
uptime of the machine you’re on. 
Obviously if you want to learn to use those commands well, you will need to do  
some homework and read their respective manual pages (with man <command>). 
The rest of this tutorial has things that require HTML to display and we like  
to keep Syndicated Echomail as textual as possible to ensure that it is  
compatible with all BBS Softwares, Mailers, Tossers, Readers and pretty much  
anything that anyone might possibly use to read mail for Xpresit Net. So, you  
can continue on via this url:  
| [TiME WaRRiOR] aka [Dave Kelso] AIM: Twar782 | +o Malkavia BBS | 
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|    @: time.warrior at malkaviabbs. com                            | 
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