The format of the access permissions, as shown with ls -l, is a list of 10 symbols:
drwxr-xr-xdrwxr-xr-x |
As Far As I Know
As Far As I Know Today
An ascii text file is a file that can directly be read by basic text editors, such as (cat, more, joe, vi, ae)
See Also: Unicode.
A feature offered by most Shells (including but not restricted to bash, tcsh, ksh and especially zsh) that allows the shell to complete a command when it can be done unambiguously. It sometimes offers a list of the possible completions. Check the Manpage for your shell for exact syntax and possible uses. With bash and tcsh, completion is achieved by pressing once on the TAB key. With ksh, it's a double strike of the ESC key...check the Manpage.
A process is said to be running "in the background" when it is not attached to a terminal. Such programs include daemons, as well as other stuff. You can put a running program into the background in bash with Ctrl+Z. Bash will list the program name and a number you can use to bring the program back to the foreground, with fg <number>.
Binary files are files that are not written in ASCII (human-readable) format, but in succession of bytes. Binary files include compiled executable files, compressed files (including images), and some data files that don't need/allow easy review.(Or that have special requirements: ciphering, size, etc...)
By The Way
One of the most powerful computer languages ever invented. Linux is written in C, as well as all UNIX systems: it is thus very portable among UNIX architectures. In fact, C was invented as a language which would make writing an operating system easier, and it was used to create UNIX in the first place. A programmer will type C Source code source code in a text editor and then compile it into a binary executable form.
See Also: Interpreters.
A compiler translates a Source code (ie human readable, ASCII) into binary (machine) code, to be executed. GCC is the GNU C Compiler, it is issued with most linux distributions.
Check it out here: The Debian University
[Remember: straight A's required to get the right to su as root :-)]
One of the many distributions of Linux. Debian's major difference is that it allows only Free software.
For any and all info, check out http://www.debian.org
There are simultaneously 3 releases of Debian GNU/Linux. One is the "stable", one the accordingly aptly named "unstable", the middle being held by "testing". The stable one is one in which development is stopped and packages are upgraded only for security-related bug fixing purposes. The "unstable" is the development one. In the "testing" release can be found packages that have survived 14 days of hard labor in the unstable area and that have been deemed fit for the service.
Please, do note that "testing" is NOT the same as "stable". Most packages that can be found in testing are OK but there can be a few surprises. A package goes into testing only if it has had no bug reports filed for it while in unstable for two weeks. Being in testing only guarantees that nobody has found any serious problems during standard use. Use caution, especially if uptime and stability are important to you (air traffic control, nuclear power plants, and the likes should definitely stay with "stable"...please do :-)
A few Debian releases:
Slink:
Debian version 2.1
kernel 2.0
Potato:
Debian version 2.2
kernel 2.2
Woody:
Debian version 3.0
kernel 2.2 or 2.4 depending on the architecture
Sid:
Debian version "Still in Development"
This version is always the "unstable" version.
The current kernel-du-jour
[little story: The names comes from the "Toy Story" (copyright to its owner and so on) movies. (In the past there were Rex, Ham, Buzz, Bo, and I think the next one may be Sarge, but I'll check). One of the early developers/project leaders of Debian was Bruce Perens, author of the Open Source definition used by the Open Source Movement. At the time, he was employed by Pixar Studios, creator of "Toy Story", and implemented Debian as the development environment for their movies.
[little story: Debian was created in 1993 by Ian Murdock. It was named after him and his wife Debra: Deb-ian (pronounce it deb-ee-ann :-)]
And last, a quote from the wise:
Debian Linux is a solid, comprehensive product, and a genuine pleasure to use. It is also great to become involved with the Debian collective, whose friendliness and spirit recalls the early days of the Internet and its sense of openness and global cooperation. | ||
--a "fortune" cookie |
depending on your sound driver,these devices are used to send/retrieve sound data:
/dev/tty* = remote terminal interface
/dev/tty?? shows up with the `w` command when you log in via hardwired terminal
/dev/pts/* = pseudo-tty - ssh or (horrors!) telnet interface
/dev/pts/* lets you interact with a command shell just like a real tty (above)
Some of those files are symbolic links to others, for example:
/dev/mouse -> /dev/psaux for PS/2 mice
/dev/cdrom -> /dev/hdc if you have an IDE CD-Rom drive
And also many others that I don't know and that you won't have to know about unless you do wild things with your linux box ;-).
"Linux" does not exist by itself. A distribution is
The kind of software, the price of it (or lack thereof), details of the implementation, all depend on the distribution.
Among them: Debian, Red Hat, SuSe, Slackware, Mandrake ... and lots of others.
They mostly differ by the tools they offer to manage and or install the system.
One of the most famous text-editors in the UNIX world. Part of the GNU project, there is a text-only version as well as a graphical one, with LOTS of "plugins" available to customize your own version. Emacs has the reputation of being able to do everything, up to but not excluding being the proverbial kitchen sink. Keep in mind that it is a fairly difficult editor to use, especially with all of the plugins installed. Many people stay away from Emacs, using the argument that an editor's job is to let you edit, and programs should do one thing well instead of everything.
a way of storing files on a medium which can be hard drives, floppies, cdroms etc,etc...
ReiserFS is a recent filesystem, designed for both speed and survivability.
iso9660 is usually the standard for CD-ROMs.
free is taken in the "freedom" sense.
It is a way of creating and distributing software with the source code and with the right to modify, upgrade and (re-)sell it as one sees fit to do, as long as the license (usually the GNU Public License (GPL)) comes along.
The term Open Source is also used to refer to software that is Free not because of ideological beliefs, but because it is a convenient way to develop programs. See http://www.osi.org>.
Open Source software includes but is not restricted to Free Software. It is also easier to convince software companies to release their sources with the term 'Open Source' than with 'Free Software', or so is it thought.
check http://www.gnu.org
For What It's Worth
Recursive acronym for "GNU's Not Unix"
The GNU project was initiated in 1984 by Richard M Stallman, a software developer at MIT's AI Lab. Its goal is to provide high-quality Free Software.
To the contrary of the symlink (symbolic link), here the actual data on disk is pointed to by more than one directory entry.
A symbolic link is merely a file that refers to another file; a hard link is actually the same exact information, located at the same spot on the disk.
With a hard link, you can pick any one of the instances of the file, and delete all the rest, and it'll still exist; with symbolic links, you can delete the target file and then all the symbolic links to it will point to a non-existent file!
But it's much easier to distinguish between an itty-bitty symbolic link and the target file, than the original doc and any other hard link to it. In fact, it's impossible, since they are the exact same thing!
Hard links are becoming more and more obsolete, in favor of soft links. I strongly suggest you use symlinks, unless you know what you are doing.
(the reference count , ie the number of hard links can be seen on the second column of an ls -l.
If you delete a file with a >1 reference count, it means the data is still stored somewhere, and accessible through another hard link,
if the reference count ==1, and you delete the file, the data will be lost and the space will actually be freed.
Don't mention reference counts smaller than 1 they are bad news :-)
The Linux Documentation Project, and in particular its HOWTO section.
The Debian FAQ, for debian-specific questions
Always try to check the HOWTOs before asking a question to a newsgroup or mailing list, or else you might get a few s.
For specific info about a command, do a man command:
man ls man csh man ps |
[your_command] --help |
Also read our NewbieDoc on the help system! :)
The core of a linux system, the kernel is loaded right after LILO starts booting linux, and starts the system according to your configuration.
It is the "conductor" of the linux orchestra.
Versions of the Kernel:
First (major) number: the "Great Number", that changes once every so often.
Second (minor)number: the release number.It is even for stable releases and odd for development ones.
Third number (patch): the update number, usually bug-fixes, or small upgrades.
[ Do NOT (as I once did :-) install a kernel with an odd minor number (i.e. 2.3 and hope it will work completely as you expect. Being odd means means this is a development kernel, paving the road for the next even, stable release. (i.e. 2.4).
AKA the LInux LOader
A small program that starts at boot time, before any OS, and that
boots linux according to specifications in /etc/lilo.conf
allows you to boot other OSes instead of Linux.
check /etc/lilo.conf for configuration
There are other tools in substitution of lilo, such as grub but lilo is the most widely used and supported.
in the truest sense of the word, "Linux" refers only to the kernel.
What most people people call "Linux" is in fact usually "GNU/Linux", at least according to the Free Software Foundation.
"Linux" comes from UNIX (of course) and Linus Torvalds, who wrote one of the first free Unix-based kernel. It was used by the GNU project as a kernel for their system while the HURD kernel was|is in development.
[By the way, some people are still fighting over whether to say lie nucks , or lee nux. Make up your mind but choose swiftly , this battle is a bloody mess ;-). Linus Torvalds had to issue a recording of how HE said it!]
They are the closest thing you may find to a "Hot-Line".
I read debian-user ( subscribe and unsubscribe at <debian-user-request@lists.debian.org> daily, but beware of its high traffic (about 100 mails per day).
A specially-formatted file that offers information about a specific command or topic.
man ls |
For more information on using the man command, see the NewbieDoc Help System document.
A file system is organized in a tree-form, with subdirectories.In order to access another filesystem (other partitions, disks,etc) one needs to mount it. That is, specify the type of the filesystem (ext2,fat...) and the directory where to put the root of the new filesystem in the directory tree.
If you have a dos disk called C in which there are the files autoexec.bat and config.sys, then the command
1 mount -t msdos /dev/hda1 /mnt/dos |
will link C:\ to directory /mnt/dos. So
1 ls /mnt/dos |
1 autoexec.bat 2 config.sys |
Linux filesystems are usually automatically mounted during the boot phase,starting with the root filesystem, and then the others: /usr, /home, etc.
check your /etc/fstab for more info
Be careful when changing /etc/fstab, don't mount /usr/local before having mounted /usr, it does not make sense...
WARNING: The directory called the mount point MUST exist and it MUST ABSOLUTELY be EMPTY prior to the mounting operation, or else you will hide files possibly needed for the system's stability.
So do NOT mount ANYTHING over / unless you really know what you are doing.
If you think you feel the need for such a stunt, take a look at the chroot command.
A general term that refers to software that has its source code included so that the consumer can modify the software if required. It is usually used as a synonym for Free Software, but it has less demands on the author than the GNU imposes. The main difference is that having software released as Open Source does not automatically give the consumer the right to redistribute the software, especially with modifications. Always check the license before trying something like that.
Linux software typically come either in tarballs or in packages.
Most distributions prefer the package form for two reasons:
It is easier to track what is installed, if it only means checking which packages (and versions).
(This is very important because, in the Linux world, software changes often)
It is a very convenient way to check that dependencies are met.
On Debian systems, use dpkg or, even better, apt-get to install, monitor, or remove packages.
![]() | Do not manage packages "by hand", by directly recompiling sources, because the package tracking system will not tak them into account and your system may stop working. |
A partition is a chunk of hard disk on which a filesystem can be built.
A hard disk can have many partitions , each with its own filesystem. This makes it possible to have two or more operating systems coexist on the same hard disk drive, each one living in its own partition(s).
"Partitioning a hard drive" means separating it into partitions. There are a number of tools to do this, among them the native Linux tools"fdisk" and "cfdisk", as well as the controversial "Partition Magic" for Windows.
Linux requires at least two partitions: one is the linux swap partition, (usually twice the size of the RAM) and the other is the ext2 root filesystem. However it is sometimes recommended to mount /usr, /home, and other directories on other partitions than the one containing the root FS.
Practical Extraction and Report Language, or Pathological Eclectic Rubbish Lister ; both names are endorsed by its author, Larry Wall.
Sometimes referred to as "The administrator's swiss army chainsaw"
Perl is a popular interpreted language, that is used very often to build system administration tools, such as debconf, or parts of some servers.
Check the current processes with ps or ps aux for all of them.
The approximate opposite of Open Source and Free Software. A data format is proprietary when its specifications are not made public.
Software is said to be proprietary when access to the source is not granted, or only to a selected panel of reviewers. Proprietary software is usually very expensive, compared to Open Source, and is often less tested.
An acronym in which the first word is the acronym itself. For example:
HURD: Hird of Unix-Replacing Daemons
HIRD: Hurd of Interfaces Representing Depth
["We have here, to my knowledge, the first software to be named by a pair of mutually recursive acronyms."], see here
One of the most powerful features of any Unix system is the "regular expression" (also called "regexp" ). It is a series of special characters that are used to design patterns, that can be used to build lists of strings (usually but not always filenames). Those lists can then be used by most command line tools. Also see wildcard...
A few examples:
rm *.hop |
rm [Hh]op |
Regular expressions are not only very useful, they are also one of the pillars of the Unix way-of-life: command line tools and regexps...
1) Administrator aka "superuser"
The root account is the all-powerful maintenance account. It can read/modify/delete any and all files on the system. It is used when installing soft/hardware, for maintenance tasks, and some processes are run under root UID.
One becomes "root" by typing
su |
![]() | DO NOT use the root account when you can use a normal user's. Even if you are the only user, if you don't need to do specifically administration tasks, then do your work as a normal user. Otherwise, you run the risk of deleting everything on your computer. The root account is very powerful. |
2) filesystem aka "/"
The root file system is the first to be mounted. It is the root of the file system tree (ergo , the name). Other filesystems are mounted on sub-directories of / (eg /usr, /home and of course /mnt ). The kernel needs to be able to mount a root file system (NEEDS ?? CHECK), so its location is specified in lilo.
Read The Fine Manual
also sometimes RFD: Read the Fine Doc.
A powerful markup language for writing documents. HTML is a compact, more specific form of SGML. For information, see Docbook.org
See Also: Extensible Markup Language.
a human readable text file. It can either be compiled into an executable program , or it can be interpreted. Being able to read the source code gives de facto complete knowledge of the program, in order to understand it, de-bug it, replicate it, etc.
See Also: Proprietary, Open Source.
These are very handy. If you have several versions of a project or file, you can
1 ln -s actual-item-being-worked-on current |
A symlink is a standalone file, removing it will NOT remove the file it points to.
Many pieces of software for Linux don't come in precompiled form, but rather as a bundle of source code files. These files are appended one to another (with the tar utility) and zipped (compressed) with gzip. Their names are often "hop.tar.gz" or "hop.tgz"
In order to install these programs one needs to unpack them (unzipping and un-tarring) and often to compile them. GNU compliant software is usually easy to compile.
Always read the README file before doing anything other than unpacking!
A number representating a user. The root user's UID is 0. A program is usually run under the UID of the person who executes it (emacs, gcc, vi) except those that need to do special things (passwd, chsh) that are run as setUID root. These are the programs that are allowed to do things that only root is allowed to do, such as changing a password, or writing things to the screen of everyone on the system. These programs must be kept to a few because of the security risk that they represent.
It's quite obvious that 8-bit ASCII can't be used to represent all the possible characters in the world (think of the chinese ideograms !). So a new encoding has been devised, called Unicode, with enough room for all possible characters of all existing languages (sort of).
"The other horrendous unix text editor. Almost as bad as Emacs (*) but _quite_ different. Variations include Elvis, Vim, NVI and others. Those who use VI tend to look down on those who use Emacs... and vice-versa. You've been warned. Wimps (or people with actual lives) tend to use midnight-commander (mc), anthony's editor (ae) or joe."... | ||
--Will Trillich (Dec. 2000) |
[for whose affirmations I will take no responsibility. I use emacs and vim, and I enjoy them all.]
A special regular expression, noted * , the wildcard is expanded to any and all possible values.
* means all possible values, hop* means all values that start by "hop", and so on...
A widely-used data representation format.
and many other (more or less correct) names (but don't just say 'Windows', argh...)
It is the system that is used to display graphical things on the screen.
Right now, the two most popular managers are the competing Gnome and KDE. Both are available in Debian.
In Unix, zipped files usually bear the extension .gz (sometimes .tgz see Tar), use gzip file to zip (compress) and gunzip file to unzip (decompress).