Login Process:
Login: user2
Password: ********
$ --> Normal
user prompt
# --> System
admin prompt
Commands:
$ logname
--> to check
present working user.
User2
$ clear
--> to clear screen
We can also use cntrl+l to
clear screen
$exit --> to quit from user
session.
Help Facility:
Syn:
1. $ man [command
name]
--> displays use and options of the command.
Ex: $ man date
Displays date command usage
and options.
$ man cal
$ man man
2. $ pwd
--> to display the present working directory
/home/user2
3. $ cal --> to display calendar (current month calendar)
$ cal 2000 --> to
display 2000 year calendar.
$ cal 08 2010
--> august month of 2010 year calendar
$ cal
78
--> 78 year calendar.
$ cal
1
--> 1st year calendar.
$ cal 10000
--> illegal year usage range upto 1-9999 only
If you pass only one
parameter after cal it considers it as year. If you pass two parameters 1st parameter
is month and 2nd parameter is year.
4. $ date
--> to
display date (displays system or server’s date which it is working)
Options:
$ date +%m --> to
display month
12
$ date +%h --> to
display name of the month
December
$ date +%d --> to
display day of month (1 to 31)
22
$ date +%y
--> to display last two digits of the year.
11
$ date +%Y --> to display four
digits of the year.
2011
$ date +%D --> to display date in
MM/DD/YY format.
12/22/11
$ date +%T --> to display time in
the format hh:mm:ss
12:30:54 H, M and S --> this options are used to display hour,
minutes and seconds.
5. $ who --> to display present working users.
User2 tty1
User3 tty3
User4 tty0
Here tty is the UNIX naming
for terminals.
LINUX naming for terminals
is Pts1, Pts2 ……
Terminal number is used
identify the clients.
6. $ finger --> displays more information about the
users like name of the user, phone number, idle time etc ..,
7. $ who am i --> displays current working
users details
User2 tty1 2011-11-12
17:20 ip address
8. $ whoami
--> displays current working user without details
User2
9. $ tty --> to display terminal type
10. $ sleep [time in
sec] --> to take the shell into sleeping state.
$ sleep 5
For 5 seconds the shell will be going to sleep state
11. Executing multiple commands
$ cmd1; cmd2; cmd3; cmd4
Ex: $ ls;
sleep 5 ; date
Here first list of the
files will be displayed then it goes to sleeping state for 5 seconds and it
displays date.
12. Wild card characters
A number of characters are
interpreted by the UNIX shell before any other action takes place. These
characters are known as wildcard characters. Usually these characters are used
in place of filenames or directory names.
*
An asterisk matches any
number of characters in a filename, including none.
?
The question mark matches any
single character.
[ ]
Brackets enclose a set of
characters, any one of which may match a single character
at that position.
-
A hyphen used within [ ]
denotes a range of characters.
~
A tilde at the beginning of a word expands to the name of your home directory.
If
you append another user's login name
to the character, it refers to that user's home
Directory.
Here are some examples:
1. cat
c* --> displays any file whose name
begins with c including the file c, if it exists.
2. ls
*.c --> lists all files
that have a .c extension.
3. cp
../abc?. --> copies every file in the parent directory that is
four characters long and
begins with abc to the working directory. (The names will remain the
same)
4. ls
abc[34567] --> lists every file that begins with abc and has
a 3, 4, 5, 6, or 7 at
the end.
5. ls
abc[3-7] --> does exactly the same
thing as the previous example.
6. ls
~
--> lists your home directory.
7. ls
~user1 --> lists the home
directory of the user with the user id user1.
8. $ ls file
[1-9] [1-9] --> in the filename 5th char should
be 1-9 and 6th should be 1-9.
Ex: file 21 file34
file 56
LINUX Wild card characters
Here are
wildcards and regular expressions:
* —
Matches all characters
? —
Matches one character
\* —
Matches the * character
\? —
Matches the ? Character
\) —
Matches the ) character
v Working with Directories
· Displaying
Directory Contents
$
ls --> To display the present
working directory contents.
Options:
$ ls
–a --> to
display all files including hidden files like . (Dot) and .. (Double dot)
files
$ ls
|pg --> to
display contents page wise (only UNIX).
$ ls
|more --> to display contents line
by line in UNIX and LINUX.
$ ls
–x --> to
display in width wise.
$ ls –x|more
--> to display contents width wise and line wise.
$ ls
–f
--> to display only files.
$ ls
–F --> to
display all files including exe files.
$ ls
–R --> to
display including sub directories recursively like tree structure.
$ ls
–r
--> to display in reverse order.
$ ls
–d --> to
display only directories.
$ ls
–t
--> to display based on date and time of creation of files (latest to
old files)
$ ls
–u --> to
display based upon last accessed time.
$ ls
–s
--> to display files including number of blocks used by the file and
directories.
$ ls
–i
--> to display files including I-node number of files. I-node number
provides
information about the files.
$ ls
–l
--> to display long list of the files.
Ex:
$ pwd /home/user2
$ ls –l
d
rwxrw_rw_ 3
user2 group1
5436 feb22
14:00 xxx
_
rw_rw_r__ 2 user2 group1
231 oct21
10:00 file1
In above example First
character is the type of the file.
_
--> Regular File
d
--> Directory File
c
--> Character Special File
b
--> Block Special File
f
--> FIFO File
s
--> Socket File
l
--> Symbolic File
· Creating
a Directory
$ mkdir [dir
name] --> To create a
Directory
· Changing
to a Directory
$ cd [dir name]
--> To change into the Directory
· To
Create Multiple Directories
$ mkdir [dir1] [dir2]
[dir3] ....
· To
move back to Parent Directory
$ cd ..
· To
move two levels up from PWD
$ cd ../..
· To
move three levels up from PWD
$ cd ../../..
· To
change to Home Directory or User Login Directory
$ cd
· To
change to Root Directory
$ cd /
Ex: To create following Hierarchy
/ (root directory)
Home (users working location)
User2 (Home directory of user which he logged in)
X
Y
X1
X2
Y1
Y2
X11
X12
Y11 Y12
$ pwd
/home/user2
$ mkdir X
$ mkdir Y
To check
whether the Directories created or not use ls command.
$ ls
X Y
Now Change into X directory
to create X1 and X2 directories.
$ cd X
$ pwd
/home/user2/X
Creating multiple
directories at once
$ mkdir X1 X2
$ ls
X1
X2
Here X is the parent
directory of X1 and X2
$ pwd
/home/user2/X
$ cd X1
$ pwd
/home/user2/X/X1
$ mkdir X11 X12
$ ls
X11
X12
Here X1 is the parent
directory of X11 and X12
Now move back to Home
Directory
$ cd
$ pwd
/home/user2
$ cd Y
$ pwd
/home/user2/Y
$ mkdir Y1 Y2
$ ls
Y1
Y2
Here Y is the parent
directory of Y1 and Y2
$ cd Y1
$ pwd
/home/user2/Y/Y1
$ mkdir Y11 Y12
$ ls
Y11 Y12
Here Y1 is the parent
directory of Y11 and Y12
To display Tree Structure
of a Directory
$ tree [dir
name]
Ex:
$ tree X
X
X1
X11
X12
X2
If you enter the Tree
command without directory name it shows current working directory tree
structure.
S pwd
/home/user2
$ tree
.
X
X1
X11
X12
X2
Y
Y1
Y11
Y12
Y2
To go to Root Directory
$ cd/
$ pwd
/
To see the Tree structure of Root
Directory line by line
$ tree | more
It will display the Tree
Structure of Root directory line By line.
· Renaming the Directory
$ mv [old name] [new name]
$ mv X Z
· Removing Directory
To Delete a Directory it should be Empty
$ rmdir [dir name]
Ex: $ rmdir x12
To Delete a Directory including Sub Directories. It is a forceful deletion.
$ rm –R [dir name]
Ex: $ rm –R Y
Y
dir along with its sub-directories is deleted.
· Working with Absolute path and Relative
path Absolute Path:
It’s a path from Root to Target Directory
(Destination)
Ex: $ pwd
/home/user2/X/X1/X11
Now we have to change
into Y2 directory in a Y directory
$ cd
[absolute path]
$ cd
/home/user2/Y/Y2
$ pwd
/home/user2/Y/Y2
$ cd
/home/user2/X/X1/X11
$ pwd
/home/user2/X/X1/X11
Relative Path:
It’s a path from Current Directory to Target Directory.
Ex: $ pwd
/home/user2/X/X1/X11
Now
change into Y2 Directory in Y Directory.
Syn:
$ cd [Relative path]
$cd ../../../Y/Y2
$ pwd
/home/user2/Y/Y2
Ex: $ pwd
/home/user2/X/X1/X11
To create an Y21 directory
in Y2 directory without moving from present working directory X11.
$ mkdir
/home/user2/Y/Y2/Y21
--> it’s by using Absolute Path.
$ mkdir
../../../Y/Y2/Y21
--> it’s by using Relative Path.
$ pwd
/home/
user2/X/X1/X11
To check the contents of Y2
directory in present working directory.
$ pwd
/home/
user2/X/X1/X11
$ ls
/home/user2/Y/Y2
--> by using Absolute Path
$ ls
../../../Y/Y2
--> by using Relative Path.
To create complete
Hierarchy as above at a time using relative path
$ pwd
/home/user2
$ mkdir
X Y X/X1 X/X2 X/X1/X11
X/X1/X12 Y/Y1 Y/Y2 Y/Y1/Y11
Y/Y1/Y12
To remove complete
Hierarchy at a time using relative path
$ pwd
/home/user2
$ rmdir
X/X1/X11 X/X1/X12 X/X1 X/X2
X Y/Y1/Y11 Y/Y1/Y12 Y/Y1
Y/Y2 Y
It is a reverse path of
mkdir to remove complete hierarchy.
· Moving
Directories
To move the Directory
including sub Directories from Source to Destination.
Syn:
$ mv [source path] [destination path]
Ex:
$ pwd
/home/user2
To move X1 directory
including sub Directories into Y1 directory.
$ mv
/home/user2/X/X1
/home/user2/Y/Y1 --> Absolute Path
$ mv X/X1
Y/Y1
--> Relative Path
· Copying
Directory contents from one location to another location including sub
directories
Syn: $ cp [option] [source path]
[destination path]
Options:
-i:
Interactive. Prompt for confirmation whenever
the copy would overwrite an existing file. A y in answer
confirms that the copy should proceed. Any other answer prevents cp from
overwriting the file.
-p:
Preserve. Duplicate not only the contents of the original file or directory,
but also the modification time and permission modes.
-R:
Recursive. If any of the source files are directories, copy the directory along
with its files (including any subdirectories and their files); the destination
must be a directory.
cp refuses to copy a file onto itself.
Ex: $ pwd
/home/user2
To copy X1 directory into
Y1.
$ cp –R /home/user2/X/X1
/home/user2/Y/Y1
(Or)
$ cp –R
X/X1 Y/Y1
Note:
The difference between copy and move command is
After copying a file from source to destination the file is available at both
source and destinations.
After moving a file from source to destination the file is available only at
destination.
v Working
with Files
· Creating
a File
Cat command is used to create a file
Syn: $ cat > [file name]
Ex: $ cat >file1
bmnxbcmnxb
cjdbcnbdncbdmns
Enter the data you want and
press (control key + d) to save & quit from file
The symbol ‘>’ is
used to enter the data into file using cat command.
With cat command we can only create a single data file. To
create multiple files is not possible through cat command it is possible
with touch command.
· Creating
multiple files
Syn:
$ touch [file1] [file2] [file3] [file4] …..
Touch command
is used to create multiple empty files. The data should be entered later using
vi editor.
· Displaying
file contents
Cat command is also used to display the data
in the file.
Syn: $ cat < [file name]
or $ cat [file name]
Here the symbol ‘<’
is optional.
Note: With cat command
we can create file and display data in the file but we cannot modify the data
of a file.
Ex: $ cat file1
bmnxbcmnxb
cjdbcnbdncbdmns
· Displaying
contents of multiple files
With cat command
multiple files data can be displayed.
Syn:
$ cat [file1] [file2] [file3] ….
The data of the files will
be displayed sequentially one after the other.
· Copying
files
To copy the data of one
file to another file cp command is used.
Syn: $ cp [source file] [destination file]
If the
destination file already exist then data of source file overrides the
destination file data. If does not exist it creates a new file.
Ex: $ cp file1 file2
If the destination file
exist, to get confirmation from user to override the data or not –i
option is used
Syn: $ cp –i [source file] [destination
file] --> to get confirmation to override.
If the file exist only it
will ask for confirmation otherwise it create new file.
Ex: $ cp –i file1 file2
Overwrite y/n? –
The file
is deleted only if option ‘y’ is entered, other than ‘y’ any char is entered
the will not be deleted.
· Rename
a File
To rename a file mv command is used.
Syn: $ mv [old name] [new name]
If the new
name already existed the old name will be renamed to new name and new name data
will be overridden by old name data.
Ex: $ mv file1 filex
Here also to get
confirmation we can use –i option.
· Removing
a file
To
delete a file rm command is used.
Syn: $ rm [file name]
Ex: $ rm file1
· Comparision
of files
To check
the differences between the data of two files cmp command is
used. But it displays only the first difference.
Syn: $ cmp file1 file2
To display all
the differences between the files diff command is used.
Syn: $ diff file1 file2
Note: Comparison between the files of different
users is possible only when the present working user has the access permission
on the other user.
· Removing
multiple files
To remove multiple
files also rm command is used.
Syn: $ rm file1 file2 file3 file4 …..
Here all
the files which are entered will be deleted. If we want confirmation
from user to delete the files –i option is used
Syn: $ rm –i file1 file2 file3 file4 ….
Ex:
$ rm –i
file1 file2 file3 file4
Remove file1 y/n? y
Remove file1 y/n? n
Remove file1 y/n?
Remove file1 y/n? x
Here
only file1 is deleted. Other than option y if you type any character the file
will not be deleted.
· Knowing
file types
To know the
type of the file, file command is used.
Syn: $ file [file name]
It displays the file type
like exe, ascii, ZIP file etc.,
Ex: $ file file1
ASCII text
$ file file.zip
ZIP archive
· Search
for a file
To search for
a file there are two types of commands. They are locate and find.
Locate command
By
using locate command we can search for the file in the entire system (OS).
Syn: $ locate [file
name] --> in whole filing system
Ex: $ locate file1
/home/user1/x/file1
/home/user2/file1
/home/file1
/file1
Find command
By
using find command we can search only in present working directory. To search
in other locations by using –name option we have to specify
the path it has to search in.
Syn: $ find [file name] --> only
search in the present working directory
$ find –name [file path] --> to search for a file in required
location
Ex: $ find –name
/file1 --> to search for file1 in
root directory.
$ find –name
/home/file3 --> to search for file3 in home directory
· wc
To count number of lines, words, chars in a
file wc command is used. By using this command multiple files
data can also be counted.
Syn: $ wc [file name]
Ex: $ wc file1
3 20
50 file1 --> here
3 lines 20 words and 50 characters
$ wc file1 file2 file3
file4
3 20 50
file1
2 10 20
file2
5 40 30
file3
6 50 100 file4
Options:
-l -->
To display only lines
-w -->
To display only words
-c -->
To display only chars
-lw --> To
display lines and words
-lc -->
To display lines and chars
-wc -->
To display words and chars
· od
od – octal dump. It shows
the binary format of file.
Options:
-b --> to
display ascii values of characters in a file
-bc --> to display ascii values of
characters along with characters.
Ex:
$ od
-b file1
00060
163
164
158 193
$ od –bc file1
00060
163 164
158 193
a
z
d c
f
· Compressing
File
Compacts a file so that it is
smaller. When compressing a file it will be replaced with a file with the
extension .gz, while keeping all the same ownership modes.
gzip is
command to compress a file. gzip is
any of several software
applications used for file compression and decompression. The term usually refers to the GNU Project's
implementation, "gzip" standing for GNU zip. It is based on
the DEFLATE algorithm,
which is a combination of Lempel-Ziv (LZ77)
and Huffman coding.
Syn: $ gzip [filename]
After compressing file into
zip file then file name will be changed to filename.zip and the original file
will not be available.
Ex: $ gzip file1
Result is file1.gz and the original file file1 will not be available.
· Uncompressing
File
To
uncompress the zip file gunzip command is used.
Syn: $ gunzip [filename.gz]
Ex: $ gunzip file1.gz
Result is file1
· Working
with archival file
Archival file is a pack
which contains hierarchy file system.
Ø Creating
archival file
“tar” is command used to
create archival file.
Syn: $ tar –cvf [user
defined name.tar] [dir name]
Here
c --> create new archival file
v --> VERBOSE is security protocol
f --> specified files
Ex:
$ tar
–cvf myarchive.tar . --> .
refer to all files in current working directory
$ tar
-cvf myarchive1.tar x --> all files in x
directory
$ tar
–cvf myarchive2.tar file1 file2 file3 file4 --> files
to be archived
Ø Extracting
archive file
To extract the
archive file tar command with option –xvf is used.
Syn: $ tar –xvf [archived file name]
Ex: $ tar –xvf myarchive.tar
Here x stand for extract
archive file
· Creating
archive file and compressing
We
can create archive a file and compress it. For doing both actions we use tar
command with –czvf option.
Syn: $ tar –czvf [userdfined
name.tar.gz] [directory name]
Ex: $ tar –czvf myarchive.tar.gz .
--> it will archive and compress the present working directory file
system and name as myarchive.tar.gz
$ tar _czvf myarchive1.tar.gz x --> x directory file
system will be archived and compressed.
· Uncompressing
and Extracting archive file
By using tar command
with –xzvf option we can uncompress and extract the archive
file.
Syn: $ tar –xzvf [archive file name.tar.gz]
Ex: $ tar –xzvf myarchive1.tar.gz
Here archive file is
uncompressed first and then Extracted. The result is original file system.
v Link
Files
There are two types of link
files
1. Hard
Link
2. soft
Link
1. Hard Link
It is a link file to another file. When the original file is deleted in Hard
link, even then we can see the data in link files.
Whenever link file is
created on original file then link counters increases.
file1
file1
filex
filex
filey
link
count=2
link count=3
To create hard link to
file1 by using a link file filex ln command is
used
$ ln file1 filex
$ ls –l
--------2---------file1
--------2---------filex
Here 2 is the link counter
number
$ ln file1 filey
$ ls –l
----------3--------file1
----------3--------filex
----------3--------filey
Here 3 is the link counter
number
$ rm file1
Even
original file is deleted data will not be deleted. data will be remained in
link files. Whenever a link file or original file is deleted just link counter
decreases. When link counter reaches to 1 the data will be deleted.
If any
changes made in original file data that affects the link file data and vice
versa. since all link files refer to the same data.
2. Soft Links
Soft link is also a link to the original file.
but when the original file is deleted link file will not work.
To create a soft link on a
file use “-s” option with ln command
$ ln –s file1 filex
$ ls –l
-l-----------1------------file1
-l-----------1------------filex
--> file1
Here l indicates symbolic
link file
$ ln –s file1 filey
------------1------------file1
-l
---------1------------filex --> file1
-l
---------1------------filey --> file1
In soft link there will be
no increment of link counter number.
when the file1 is deleted
other link files on file1 will not work.
v FTP
(File Transfer Protocol)
File
Transfer Protocol (FTP) is a network protocol used to copy a file from one
computer to another over the Internet or LAN. FTP follows a client-server
architecture which utilizes separate control and data connections between the
ftp client and server.
To connect to FTP server
enter ftp command in user mode. Now $ prompt changes to ftp
prompt there open the server connection by using ip address and password.
Syn: $ ftp
ftp >
open 192.14.35.76
Password:
********
To close the server
connections close command is used.
ftp> close
237 goodbye
To come out from ftp to $
prompt bye command is used.
ftp> bye
$-
Commands used in ftp
ftp>
verbose
--> Verbose mode gets off.
ftp>
pwd
--> To display server’s current working directory
ftp>
lcd
--> To display client’s current working directory.
ftp>
ls
--> To display server’s directory contents.
ftp>dir
--> To display server’s directory contents.
ftp> mkdir [dir
name] --> To create a directory on server.
ftp> cd [dir
name] --> To
change a directory on server.
ftp> rmdir [dir
name] --> To delete a directory from server.
ftp> delete [file name]
--> To delete file on server.
ftp> mdelte file1
file2.. --> To delete multiple files on server.
ftp>
binary
--> To set the transfer mode as binary
ftp> put
[filename] --> To
upload the file
ftp> mput file1
file2.. --> To upload multiple files
ftp> mput
*.cpp
--> To upload all the files with extension .cpp
ftp> get [file
name] --> To download the
file
ftp> mget
*.cpp
--> To download the multiple files with extension .cpp.
ftp> disconnect
--> To disconnect from server.
ftp>
quit
--> To quit from ftp prompt
ftp>
bye
--> disconnecting from server and quit from ftp prompt.
ncftp --> Anonymous
ftp
$ ncftp
192.65.78.90 --> To connect to the ftp site
without UID and PWD.
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Thank you :
- kareem