Unix

1
Unix

• Getting Started in the Unix Environment

2
Unix Commands

• Arcane and Funny looking
• Counter intuitive
• Case Sensitive!!
• FILENAME filename Filename
• All commands in lowercase

3
General Information

• The shell we use is called csh
• favors C programming syntax
• called C shell

4
Command Syntax

• Command flags argument1 argument2
• ls l

5
Correcting Typos

• ltDELgt or ltBACKSPACEgt deletes previous character
• ltCTRLgt ltwgt -- erases previous word
• ltCTRLgt ltugt --erases entire line

6
Files and Directories

• Pathnames
• Begin with a forward slash /
• Example type pwd
• Returns /home/username
• This is called your home directory.
• Home directory is not that same as the system
  root directory. Think of your home directory as
  the very small section of the unix system I call
  my own
• A / at the end of a URL indicates that the URL
  is pointing to a directory and not a file. By
  default, most servers are configured to display a
  specific file usually called index.html.

7
Naming Directories

• Usually a single word
• NO SPACES
• Lowercase
• Example create the directory personal using
  mkdir
• /. Current directory
• /.. Parent directory

8
Naming Files

• Filename
• Extensions
• Determine the type of the file
• Examples
• .txt
• .html
• .cgi
• .gif
• .jpg
• Filenames that begin with . are hidden and
  will not appear unless a special directory
  command is used.

9
Online Manual

• Eight Sections
• Commands
• System calls
• Library functions
• Devices and device drivers
• File formats
• Games
• Miscellaneous
• System maintenance

10
Syntax

• man command
• Example man cp
• Example man ls
• ltCTRLgt ltcgt to exit the manual.

11
Basic Commands

• passwd changes the users password
• exit or bye exits the system
• ls
• -l lists files in long format
• -a lists hidden files as non hidden files
• -c forces a column output
• -t sorts by last modification time

12
Navagation

• cat displays the contents of a file
• cd change directory
• EXAMPLE cd ..
• EXAMPLE cd public_html
• EXAMPLE cd n241
• EXAMPLE cd ../.
• WHERE ARE WE?!?!?

13
Copy

• cp puts a duplicate in another location, leaves
  the original untouched
• Syntax cp oldfile newfile
• Copies Files
• EXAMPLE cp ../../opt/local/examples/test.txt
  helloworld.txt
• cp helloworld.txt public_html/helloworld.txt
• cp .txt n241/lectures

14
Move and Remove

• rm removes files
• EXAMPLE rm helloworld.txt
• answer yes to confirm.
• mv moves files
• syntax mv oldfile newlocation
• mv helloworld.txt public_html/n341
• can also rename files
• mv helloworld.txt helloworld2.txt

15
Make a Directory/Remove a Directory

• mkdir - Makes a directory
• EXAMPLE mkdir funexample
• cd funexample
• rmdir removes a directory
• cd to home/usrename/ if necessary
• rmdir funexample

16
Permissions

• Controls who can read write and execute through
  your files.
• ls l
• -rw-r--r permissions
• 1 jstudent owners username
• students owners group
• 881- size in bytes
• Jan 13 1525 time last modified
• index.html file name

17
Permissions codt

• Directories usually have 7-5-5 rights
• Files normally have 7-5-5 rights
• exception executable files .exe or .cgi
• we use 6-4-4
• chmod changes the permissions
• syntax chmod permission file
• EXAMPLE chmod 644 index.html
• chmod 644 . changes permissions of all files in
  a directory.

18
Other Commands

• finger username gives information about a user
• cls clears the screen
• who who is logged into the server at any give
  time
• cal- calendar of the current month
• date gives the current system date
• !! bang bang repeats the last command
• ! - bang symbol with the number of the last
  command