Several years back a relative asked me what I do for a living.
I told him I work with UNIX. He thought I said, "Eunuchs" and
asked if I found that rather disturbing...
Nothing seems to stir dread in Windows and DOS users more
than being faced with the prospect of having to use UNIX for the
first time. Yes its true that UNIX is a very sophisticated
operating system with a million commands, but you can most
likely do everything you need as a webmaster with just
a few of them. Think about what commands you use most
of the time with DOS!
What you need to find out
are the locations of home directories and web directories.
Your host or service provider can fix you up with this information.
This page is a quick introduction to the several commands
and things you need to know about UNIX. Believe me, you can
learn about UNIX on the 'Net- in fact most of the Internet
runs on UNIX servers. Print out this page, put it on your
lap- and voila you too are a UNIX Guru!
Fear not the FUD.
I cannot stress this strongly enough. In case you are not
familiar with the acronym "FUD", it stands for Fear,
Uncertainty and Doubt. One of the more popular operating
system and software vendors loves to publish documents
explaining why Unix is so hard to learn, and therefore
pretty much useless, except to a small group of geeks.
They also put forth the argument that unix is based on
30 year old technology, and that makes it bad as well.
Well, if it makes you feel any better, the majority of
the sites on the Internet- especially the large ones,
run on unix servers.
As far as 30 year old technology goes, don't you think
us geeks would be the first people to adopt a "new"
technology if it were in fact better, especially if it
were "easier" to learn? Want to know a secret? The GUI
interface existed on unix a long, long time ago...
So forget the FUD and read on...
Important Differences Between UNIX and DOS
Despite common belief, switching your mindset from DOS to UNIX
is not very hard. There are several things you should be aware
of that will instantly make your life easier.
The end of file character is control-D, not
UNIX ends its lines with only a control-J. Remember
to FTP your HTML and text files from DOS to UNIX
using ASCII mode. If you end up with control-M's
in your scripts, they most likely won't run.
UNIX is case sensitive. It is important to remember
that IMAGE.JPG and image.jpg are not the same.
The normal convention in UNIX is to use lower case
letters, but this is not law.
In UNIX, you do not use the backslash, but rather
the forward slash when referencing directories. The
backslash tells UNIX to take the character after it
literally. So cd \dir\dir would be cd dirdir.
cd with nothing after it takes you to your home
directory, it does not print out your present working directory.
That would be the pwd command!
UNIX does not have an unerase command. Once you delete
a file, it is gone forever.
Command options in UNIX generally use the hyphen-, not the
Navigation: Same commands, but...
Getting around in UNIX is very similar to getting around in DOS.
The only source of confusion is that when Bill Gates decided
to have PC-DOS support a tree directory structure, he had his
car running in the garage that night. In other words- Whenever
you have an urge to hit the backslash, hit the forward
slash key instead.
Unlike DOS, UNIX has no concept of drive letters. UNIX uses what
are called mount points such as /usr or /usr/local or /var. This
is especially convenient when one has more partitions or shares
to mount than there are letters in the alphabet!
pwd tells you what directory you are in.
cd alone returns you to your $HOME directory.
cd .. takes you up one level.
cd dirname moves you to the directory named "dirname".
Unix and DOS have the same utilities for dealing with files
and directories- only some of the names have been changed...
cp Works just like copy in DOS.
Syntax: cp file1 file2
rm Replaces the DOS erase command.
Syntax: rm file
mv Does what rename does in DOS.
Syntax: mv file1 file2
mkdir is the same as in DOS.
Syntax: mkdir dirname
rmdir is the same as in DOS.
Syntax: rmdir dirname
ls is the UNIX version of dir.
Syntax: ls -l shows long (detailed) listing.
Syntax: ls -last shows long listing- newest first.
Syntax: ls -c is like dir /W
DOS has a limited utility for setting permissions on files: ATTRIB.
In UNIX (being that it is a true multi-user, multitasking operating
system), has a more sophisticated method of setting permissions: the
chmod command. To understand it, let's look at a small directory
listing as made with the ls -l command.
The permissions are indicated by a series of rwx's on the left
side of the listing. The first position indicates the type of
file. For our purposes it is always a "-" for a file, or a "d"
for a directory.
The remaining nine characters indicate the permissions given to
the owner, group, and others. Since owner and other both start
with the letter "O", think of owner as the user. Here is
the nitty gritty...
X means execute permission- except for directories
where it means search permission.
The first three permission characters are for the user (owner),
the middle three are for the group, and the last three are for
all other people on the system.
chmod 775 dirname is the normal permission for a
chmod 664 filename is the normal permission for a
non-executable file, i.e., an HTML or image file.
chmod 775 filename is the normal permission for
an executable file, i.e., a shell script. Usually these
are not in your web directory.
Many of you without telnet access that use an FTP
program such as Cute-FTP or WS-FTP, will have to use the unix
command function of your program. Check the help file with your
FTP program for the exact instructions.
The main editors available on most UNIX systems in order of
vi. The most popular UNIX editor. Can be found
on every system. Takes some getting used to, but is very
addictive! recommended.Here is an excellentQuick tutorialby Tony Thomas.
emacs. Very powerful. Very complicated.
pico. On screen reminders of comand keys.
For more documentation...
Every UNIX system has on-line documentation. It is identical
to the paper manual pages. In order to use this feature, you
must be able to access your site and login using a TELNET
Getting help is as simple as entering the command:
The man command will format and display the manual pages
for the command you request. Not all of the instructions you
will find will make much sense as ALL options for a command are
presented, but most have simple examples.
Guess what? You have graduated! This pretty much covers the
material of a two day Introduction to UNIX course- retail
value is about $595.