CSC128: Introduction to Linux

Basic Commands

Passwords

A good password is easy to remember, but difficult to guess. Don't write your password down; try to pick one that you can remember using mnemonics. For example, if you were born on April 1, 1965, apR#01nsf might be a good password .

Good passwords include letters (both cases), numbers, and symbols.
Good passwords are at least six characters long.
Good passwords do NOT use words that can be found in any dictionary or proper names at all.

Examples of bad passwords:

password
Billy1
39578
j0hns0n
s2

Examples of good passwords:

25bgsF$
bB76##-
tNfS8!
jJ100@nN

Use the passwd command to change your password. (This may be different on other systems.)

NOTE: you should definitely change your password from the default password given to you.

Shells

tty, terminal emulators (pp. 25-26)

• Ctrl-H/Ctrl-?: Backspace
• Ctrl-W: Erase a word from the command line
• Ctrl-U: Erase entire line
• Ctrl-C: Abort execution

Shell prompt

• $ or % or > which is our prompt
• # usually means root (which is the login name of the system manager)

Exiting the shell

• exit , logout, Ctrl-D

Some shells: bash, sh, tcsh, ksh, zsh, etc.

We will only be studying and using the bash shell.

Files

Everything in Linux is a file.

Text (e.g. source code), programs, directories, access to devices (peripherals, etc.), streams of data, etc. are all files.

Just type the name of a program to execute it. If it isn't in the current search path, then you must type the pathname with the filename.

Linux searches many directories to find the program you wish to run-the directories it searches is called the search path.

A pathname is the way we tell Linux about the location of a file we wish to use.

For example: /home/students/a/abear/test_file. Here, /home/students/a/abear/ is the pathname, and test_file is the filename.

We will discuss this in greater depth later, when we talk more about filesystems.

Basic Commands