1.1 Logging into the Unix System

To gain access to Unix systems, you must go through a login process. Usually this is done by telnet-ing to a Unix system. e.g. on a Windows 95 system with the Internet package installed, at the command prompt you type

c:\>telnet telnet.netfront.net

the following should appear on a pop-up screen:

Trying 202.81.252.254...
Connected to telnet.netfront.net.
Escape character is '^]'.

Linux 2.0.29 (telnet.netfront.net) (ttyp0)

telnet login:

To log into the system you simply type your user name, and then press the carriage-return key. Then type in your password, press the RETURN key again. The UNIX system prompt % will then appear.

1.2 Terminal Type

You have to set the correct terminal type for the Unix system to display on your window properly, this is done by setting the term environmental variable. In most cases, the following command

telnet-demo 10% set term=vt100

will be okay.

1.3 Signing Off

Type "logout" to log out from UNIX.

1.4 Getting Help

In UNIX, there are just too many commands which make it difficult to remember all. From time to time you will need to refer to their help information or manuals. You can access the manual of any UNIX commands by using the man command. E.g. to read the manual for the man command itself, you type

telnet-demo 14% man man

Files and Directories

Files and Directories are organized in a tree structure similar to DOS. The path name separator is "/" instead of "\" as in DOS.

2.1 Printing Working Directory with pwd

The full pathname of the current directory will be displayed.

DOS counterpart: N/A

2.2 List Directory Contents with ls

-a list all files, including directories and hidden files
-C list in column form
-d list status of directory (together with -l)
-F show file type
-g list group
-l long listing
-r reverse order listing
-R recursive listing
-t on time sequence

DOS counterpart: dir

2.3 Changing Working Directory with cd

cd alone will bring you to the home directory

DOS counterpart: cd

2.4 Looking at the Contents of a File with cat

-b, -n number the lines
-s substitute a single blank line for multiple adjacent blank lines
-v display non-printable charaters

DOS counterpart: type

2.5 Looking at the Content of a File with more

telnet-demo 100% more /etc/motd

DOS counterpart: more

2.6 Looking at the End of a File with tail

telnet-demo 101% tail /etc/motd

DOS counterpart: N/A

2.7 Copying File with cp

cp file1 file2
cp file dir
cp -r dir1 dir2

-i interactive
-p preserve modification time and permissions
-r recursively coping files in subdirectories

DOS counterpart: copy

2.8 Creating Directories with mkdir

DOS counterpart: md

2.9 Moving and Renaming Files with mv

-i interactive
-f override any mode restriction and -i option

DOS counterpart: move

2.10 Removing Files with rm

-i interactive
-f force files to be removed
-r recursively remove files

DOS counterpart: del

2.11 Removing Directories with rmdir

DOS counterpart: rd

2.12 Ownership and Protection

The first character of a directory listing with the ls -l command indicates the file type.

telnet-demo 122% ls ?/FONT>l

total 401
drwxr-x--- 2 demo 512 Apr 10 13:14 pub
-rwxr--r-- 1 demo 6442 Mar 24 21:00 README
-rwxr--r-- 1 demo 14 Apr 18 17:41 account.txt
-rwxr--r-- 1 demo 25293 Apr 23 19:53 log

d entry is a directory
- entry is a plain file
The next 9 characters designate access permissions.
r the file is readable
w the file is writable
x the file is executable
- the indicated permission is not granted

The chmod command can be used to change the file permissions.

owners operator permission
u users + add r read
g group - subtract w write
o others = assign x execute

e.g. telnet-demo 123% ls ?/FONT>l README

-rwxr--r-- 1 demo 6442 Mar 24 21:00 README
telnet-demo 124% chmod go+w README
telnet-demo 125% ls -l README
-rwxrw-rw- 1 demo 6442 Mar 24 21:00 README

The Electronic Mail System

The following are some the most popular e-mail programs for sending and reading E-Mail, use the man command to learn how to use them.

mail
elm
pine

Text Editing

vi
emacs
pico

Use the man command to learn how to use them.