Làm quen với linux

Lab 1:

Working with Linux

1


Login and logout
• Account
– username & password
– Note:
• Linux is case-sensitive
• Administrator: username = root

• Logout: exit, Ctrl+D

2


Linux File System
(C)

WINDOWS

Fonts

(D)

Program Files

System32

….

Data

OS

….

Windows File System

(/)

Music

….

boot

….

home

khoa

etc

root

student1

….

Linux File System

3


Directory/file commands
• List contents of directory :

ls [-a] [-l] [directory_name]

• Print working directory: pwd
• Change working directory :

• Create new directory :
• Remove a directory:

cd directory_name
E.g. cd /home

mkdir directory_name

rm -r directory_name
• Some special symbols :
~ : home directory
.. : parent directory
4

Directory/file commands
• Display file content :
cat filename or more filename
head filename or tail filename
• Copy file(s) or directory:
cp [-r] source_file destination_file
• Remove file or directory
rm –r file_name
• Move (rename) file(s)/directory
mv old_path new_path
5


File system and
permissions
• Each user may owns one or more directories/files
• Each user has different access rights in different
directories/files
users can share their data together
users also can protect their private data

6


File system and
permissions
• Access right on directory/file
– read (r)
– write (w)

– execute (x)

• Each directory/file has 9 access-right bits, divide into 3 groups as
follow :
– owner
– group (e.g. people the same project team)
– others (people in public domain)

7


File system and
permissions

8


Changing access rights
(1)
• Symbolic
chmod who op mode [-R] file(s)

• Who:

u : owner

• Mode:
• Op

g : group

o : others
a : all
r : read

w : write
x : execute

+ : grant more rights

- : revoke rights
= : reset rights
9


Changing access rights
(2)
• Example
$ touch temp
$ ls –l temp
-rw-r--r-- 1 user1 staff 0 Jun 11 11:44 temp
$ chmod o-r temp

$ ls -l temp
-rw-r----- 1 user1 staff 0 Jun 11 11:44 temp
$ chmod u+x, o+r temp
$ ls -l temp
-rwxr--r-- 1 user1 staff 0 Jun 11 11:44 temp

10

Changing access rights
(3)
• Numeric: chmod xyz [-R] file(s)
read = 4

write = 2 execute = 1
Octal value

Access right

7

rwx

6

rw-

5

r-x

4

r--

3

-wx

2

-w-

1

--x

0

--11


Changing access rights
(4)
• Example: some common access rights of
directory/file(s)
Octal value

Access right

600

rw-------

644

rw-r--r--

700

rwx------

751

rwxr-x--x

775

rwxrwxr-x

777

rwxrwxrwx

12


Changing access rights
(5)
• Example
$ touch abc
$ ls –l abc
-rw-r--r-- 1 user1 staff 0 Jun 11 11:44 abc
$ chmod 555 abc

$ ls -l abc
-r-xr-xr-x 1 user1 staff 0 Jun 11 11:44 abc
$ chmod 775 abc

$ ls -l abc
-rwxrwxr-x 1 user1 staff 0 Jun 11 11:44 abc

13


Advanced utilities (1)
• Who is who?
who [option]

• Print current host name
hostname

• Where do they come from?
which [filename]

• How much disk usage?
df [option]

• Clear screen
clear

OR

Ctrl + L
14


Advanced utilities (2)
• Find a specified file :

find path –name filename
• Find lines in file matching a pattern
grep pattern file_name
• Mount and unmount file system
mount -t filesystem device_file mount_point
umount mount_point

15


vi editor
• Interactive simple editor
• Can not use mouse
• Text editing on a buffer
• Appears on most Unix or Unix-like system
16


vi usage
syntax

meaning

vi filename

open/create file

a or i

change to edit mode

ESC → wq!

save and quit

ESC → q!

not save and quit

17


Cursor movement in vi
Cmd

Meaning

n

move cursor left n character(s)

n

move cursor down n character(s)

n

move cursor up n character(s)

n

move cursor right n character(s)

Enter move cursor to beginning of next line
G

move cursor to the last line

nw

move cursor left n word(s)

nW

move cursor right n word(s)

18


Cmd

Text manipulation
commands

Meaning

nx

delete n character(s) from current cursor
position

nX

delete n character(s) immediately preceding
current cursor position

D, d$ delete all characters from current cursor
position to end of line
d0, d| delete all characters from left collumn of
screen to character preceding current cursor
position on current line

19


Cmd

Text manipulation
commands

Meaning

ndd

delete n line(s) beginning at current line

dG

delete all lines, starting with current line, through
end of file

d1G

delete all lines, starting with current line, through
beginning of file

ndw

delete from cursor position through end of n
following word

ndb

delete from nearest preceding word through
character before current cursor position

J

join the next line at the end of current line

20