Many of us have access to UNIX through our ISPs. This tutorial is aimed at those people especially. But most of the tutorial would work on any UNIX system. And if you don't have access to a UNIX system, reading the exercises should still give you the basic idea.

The exercises don't create, delete or change any user data. So you are not likely to do any damage by doing these exercises.

Presupposition

If you want to do these exercises (not just read them), you'll need the following (or some rough equivalent).

a web site with a few html pages and ideally some subdirectories.
A UNIX shell account with your ISP allowing you to access your web site with Telnet.
The name of the host your web site is on.
Your login name and password.
A system with Telnet, etc. to connect with.

Conventions

The following conventions are used in the exercises below.

The UNIX prompt, commands you key in and the system responses are all highlighted in grey.
In the exercises, anything in bold is user input.
At the end of a line of your input, you'll need to supply a Return.
Everything else is from the system.
The > at the beginning of the line is the UNIX command line prompt.
Your prompt could be different.

Since I don't know what's on your system, you'll need to tailor the exercises to your own site.

1. Connecting to the Host

Having connected to your ISP, bring up Telnet and supply the host name of the computer your web site is on, e.g. users.lanminds.com (in my case)

In the example, I've used the host name of the computer my personal site is on. You would use the host name supplied by your ISP instead.

2. Logging in

When prompted, key in your login name and then your password.

SunOS 5.7
   
login: metaart
Password:
Last login: Mon Apr  5 18:12:39 from coat4.ppp.lmi.ne
Sun Microsystems Inc.   SunOS 5.7       Generic October 1998
   
>

Your login name will be the one you arranged with your ISP rather than metaart. The example does not show the password because it is not echoed back. But you will need to key in the expected password.

3. Looking Around Your Home Directory

Key in the pwd command to see the path to the current directory.

> pwd
/data1/home/metaart

This tells us

the current directory is named metaart
and is a subdirectory of the home directory
which is a subdirectory of the data1 directory
which is a subdirectory of the root directory, i.e. of /

This directory which you start in each time you login, is called your home directory.

Now do an ls command to see what files and directories are within the current directory.

> ls
www

OK. This shows that www is within the current directory. But is it a file or a directory? Key in an ls command with a -l (long) option.

> ls -l
total 2
drwxr-xr-x   8 metaart  users       1024 Mar 15 01:40 www

This tells us, among other things, that www

is a directory. The initial d tells us that.
and takes up 1024 bytes.

Of course, what you see will be somewhat different. The path for your directory will be different, etc.

4. Learning about a Command through a man page

You can find out more about most commands (and many other subjects) with the man command. Here, we look for information about how to list the names of files which have names beginning with a dot (which are otherwise not shown).

> man ls
Reformatting page.  Wait... done
   
User Commands                                               ls(1)
   
NAME
     ls - list contents of directory
   
SYNOPSIS
     /usr/bin/ls  [ -aAbcCdfFgilLmnopqrRstux1 ]  [ file ... ]
   
     /usr/xpg4/bin/ls  [ -aAbcCdfFgilLmnopqrRstux1 ]  [ file  ... ]
   
DESCRIPTION
     For each file  that is a directory, ls  lists  the  contents
     of  the  directory; for each file  that is an ordinary file,
     ls  repeats its name and any  other  information  requested.
     The  output  is  sorted  alphabetically  by default. When no
     argument is given, the current  directory  is  listed.  When
     several  arguments are given, the arguments are first sorted
     appropriately, but file arguments appear before  directories
     and their contents.
   
--More--(4%)

Since you haven't yet found what you want, hit the space bar to see the next page. Continue doing that until you see something like:

.....
OPTIONS
     The following options are supported:
   
     -a        List all entries, including those that begin  with
               a dot (.), which are normally not listed.
.....

Press q to stop looking at the output from man.

Now enter an ls command using the -a option described to see the hidden files, which have names starting with dot.

> ls -a
.         ..        .cshrc    .history  .login    www

5. Looking Around Your Directories

As we mentioned at the start, you'll have to modify these examples to do these exercises on your account and your site.

Key in an ls -R command to see the structure of your directories and subdirectories (and the files in them) starting with the current directory (i.e. your home directory). This will give you an idea of what directories to use in the following exercises instead of the one's I used.

> ls -R
.:
www

./www:
GW_articleson.html         index.html
GW_favorites.html          isabelle
GW_poems.html              resume

.....

./www/isabelle:
index.html              isabelle_19981106.html  isabelle_pic2.jpeg
isabelle.css            isabelle_19981231.html  
isabelle_19981020.html  isabelle_pic1.jpeg

.....

./www/resume:
GW.css                 GW_resume_faqs.html    index.html
GW_resume_chron.html   GW_resume_skills.html

The structure that we see includes:

the home directory
within the home directory, the subdirectory www
within the www directory, the subdirectories resume and isabelle
plus 4 html files
within the isabelle directory, 7 files
within the resume directory, 5 files

Change directories to the www directory within the current directory.

> cd www
> pwd
/data1/home/metaart/www

Now change directories to the parent directory. In UNIX .. refers to the parent directory.

> cd ..
> pwd
/data1/home/metaart/www

Now change directories to the resume directory within the www directory within the current directory.

> cd www/resume
> pwd
/data1/home/metaart/www/resume

Now go back to your home directory by using cd with no arguments.

> cd
> pwd
/data1/home/metaart

6. Finding Files

Use the find command to search for jpeg files (or some other kind of file you have) in all of your directories, starting with the current one (which is your home directory).

> find . -name " *.jpeg" -print
./www/family/GW_pic_RWES.jpeg
./www/family/GW_pic_RWJW.jpeg
./www/family/GW_pic_Sand3.jpeg
./www/friends/GW_pic_EHJW.jpeg
./www/friends/GW_pic_GWJW.jpeg
./www/friends/GW_pic_GWLC.jpeg
./www/isabelle/isabelle_pic1.jpeg
./www/isabelle/isabelle_pic2.jpeg

The * is a wild card, so *.jpeg searches for all files ending in .jpeg. Don't forget the -print. If you do, all the work will be done, but nothing will print.

7. Checking Space Usage

Most ISPs have limitations on how much space you are allowed to use. Check to see how much you are using using the du command.

> du
36      ./www/george
206     ./www/octagon
192     ./www/family
240     ./www/friends
144     ./www/isabelle
36      ./www/resume
924     ./www
932     .

You are using 932 blocks. But what size are the blocks? In UNIX it's typically 512 bytes or 1024 bytes. Notice that the www/resume is using 932 blocks. Let's do an ls -l of that directory and see if we can tell the block size.

> ls -l www/resume
total 34
-rw-r--r--   1 metaart  users        508 Mar 15 01:38 GW.css
-rw-r--r--   1 metaart  users       2892 Mar 15 01:38 GW_resume_chron.html
-rw-r--r--   1 metaart  users       3281 Mar 15 01:38 GW_resume_faqs.html
-rw-r--r--   1 metaart  users       7201 Mar 15 01:38 GW_resume_skills.html
-rw-r--r--   1 metaart  users        556 Mar 15 01:46 index.html

The way of measuring space is obviously different in du and ls. But it's clear a block size of 1024 bytes is much too high. So we'll assume that the block size is 512 bytes. That being so:

932 blocks * 512 bytes =
932 blocks * 1k/2 = 466K = about 1/2 meg.

Since I'm allowed 25 meg, I'm OK.

Note: Or it might have been simpler to use du -k instead of du earlier. That would have caused du to report in kilobyte units.

8. Looking Inside a File

Change to a directory containing a file to look at, and checkout what's in the directory.

> cd www/isabelle
> pwd
/data1/home/metaart/www/isabelle
> ls
index.html        .....
.....

Using cat display the contents of a file you are interested in.

> cat index.html
<HTML><HEAD>
<TITLE><Isabelle/TITLE>
.....
<HR>
</BODY>></HTML>

9. Searching the Contents of a File

Change directories to a directory containing some HTML files and do a search on some tag. Here we search on the IMG tag.

> cd www/isabelle
> grep "<IMG " *.html
index.html:<IMG SRC="isabelle_pic1.jpeg" BORDER=3> <IMG SRC="isabelle_pic2.jpeg"
 BORDER=3>

Here we searched for IMG tags within www/isabelle, restricting ourselves to files with names ending in .html.

10. Logging Out

Finally, logout.

> logout

Your connection is broken.