Linux Questions, Week 9
| Published 12/3/04

 


Graphic by: Larry Ewing
Johnny asks: "Do Linux programs have help files, like programs in Windows and Macintosh?"

Yes. The command "man" displays a help file, or manual for a Linux application. The manual pages are typically divided up into sections numerically. Section 1 usually contains user commands, section 2 system calls (functions provided by the kernel), section 3 library calls (functions within system libraries), section 4 special files (usually found in /dev), section 5 file formats and conventions (e.g., /etc/passwd), section 6 games, section 7 macro packages and conventions, section 8 system administration commands (usually only for a privileged user), section 9 kernel routines (nonstandard). You can pass one of these section number with the command to display a particular section. If you're using KDE, the Konqueror browser will display man files. Otherwise, use the terminal to run the command.


Samantha asks: "I downloaded some stuff for my new Linux system and it's a '.tar' file. What is this, and what do I do with it?"

Tar files are archives, like .zip in Windows. The extension actually stands for "tape archive. You unzip it using the command:

tar [options] [filename]

As with most Linux commands, there are a ton of options you can pass with this command. You can see these options listed in the tar section of the Linux command directory at O'Reilly

Or, you can just run your x window system and double click on the file.


Tootsie asks: "What's the command to change the permissions on a file?"

Use the command chmod to edit permissions. Remember, only the owner of a file or a privileged user can change the mode. Therefore if you can't change the permissions, either the file isn't yours and you shouldn't be messing with it, or you need to log in as root or switch to superuser mode. The following options designate who can access a file:
u, User
g, Group
o, Other
a, All

And these are the most common options for what those people can do with the file:
r, Read
w, Write
x, Execute

Use + to add a permission, - to remove a permission, and = to assign a permission.


That's it for this week. Check back next week for more Linux questions. If you have a Linux question, you can submit it in the responses form below, or email it to mailto:jconner28@radford.edu

 

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