Linux Tutorial
Operating system?
operating system is an interface between user and computer hardware.the hardware of the computer cannot understand the human readable language
as it works on binaries eg 0 's and 1 's .also it is very tough for humans
to understand the binary language,in such case we need an interface
which can translate human language to hardware vice-versa for effective
communication.
Types of operating system?
- single user--single tasking operating system
- single user--multitasking operating system
- multi user--multitasking operating system
single user--single tasking operating system
in this type of operating system only one user can login into the system
and can perform only one task at the time.
EG:MS-DOS
single user--multitasking operating system
this type of operating system only one user can login into the system
and can perform multiple task at the time.browsing internet while playing songs.
EG:WINDOWS -98,XP,VISTA,7,8,10 etc.
multi user--multitasking operating system
this type of operating system provides multiple users to log into system and also each
user can perform various tasks at a time
EG;UNIX,LINUX etc.
and can perform only one task at the time.
EG:MS-DOS
single user--multitasking operating system
this type of operating system only one user can login into the system
and can perform multiple task at the time.browsing internet while playing songs.
EG:WINDOWS -98,XP,VISTA,7,8,10 etc.
multi user--multitasking operating system
this type of operating system provides multiple users to log into system and also each
user can perform various tasks at a time
EG;UNIX,LINUX etc.
linux architecture
the main concept that unites all the versions of unix is the following four basics-
1.kernel-the kernel is the heart of the operating system.it interacts with the hardware and most of the task like memory management,task scheduling and file management.
2.shell-the shell is the utility that processes your requests.when you type in a command at your terminal,the shell interprets the commands and calls the program that you want.the shell uses
standard syntax for all commands.C shell,Bourne shell and Korn shell are the most famous shells which are available with most of unix variants.
3.commands and utilities- there are various commands and utilities which you can make use of in your day to day activities.cp,mv,cat,and grep,etc.are few examples of commands and utilities.there are over 250 standard commands and numerous others provided through 3rd party software.all the commands come from various option.
4.files and directories-all the data of unix is organized into files.all files are then organized into directories.these directories are further organized into a tree-like structre called the file system.
1.kernel-the kernel is the heart of the operating system.it interacts with the hardware and most of the task like memory management,task scheduling and file management.
2.shell-the shell is the utility that processes your requests.when you type in a command at your terminal,the shell interprets the commands and calls the program that you want.the shell uses
standard syntax for all commands.C shell,Bourne shell and Korn shell are the most famous shells which are available with most of unix variants.
3.commands and utilities- there are various commands and utilities which you can make use of in your day to day activities.cp,mv,cat,and grep,etc.are few examples of commands and utilities.there are over 250 standard commands and numerous others provided through 3rd party software.all the commands come from various option.
4.files and directories-all the data of unix is organized into files.all files are then organized into directories.these directories are further organized into a tree-like structre called the file system.
file system
1. \
it is a parent directory for all other directories it is called as ROOT directory.it is represented
by forward slash (/).
c:\ of windows.
2. \root
it is a home directory for root user (super user).it provide working environment for root user
\root is similar to c:\documents and settings\administrator.
3. \home
it is a parent directory for all other directories it is called as ROOT directory.it is represented
by forward slash (/).
c:\ of windows.
2. \root
it is a home directory for root user (super user).it provide working environment for root user
\root is similar to c:\documents and settings\administrator.
3. \home
it is a home directory for other users.it provide working environment for
other users(other than root).
4. \boot
other users(other than root).
4. \boot
it contaons bootable files for linux,like vmlinuz(kernel)...
initrd (INITial Ram Disk) and GRUB (GRand Unified Boot loader)....
boot.ini,ntldr.
5. \etc
initrd (INITial Ram Disk) and GRUB (GRand Unified Boot loader)....
boot.ini,ntldr.
5. \etc
it contains all configuration files like /etc/passwd -user info,
/etc/resolv.conf-Preferred DNS,/etc/dhcp.conf-DHCP server
/etc is similar to c:\windows\system32\drivers\.
6. \usr
By default softwares are installed in usr directory(UNIX Sharable Resources)
\usr is similar to c:\Program Files.
7. \opt
\usr is similar to c:\Program Files.
7. \opt
it is optional directory for /usr.it contains third party
softwares /opt is similar to c:\Program Files.
8. \bin
softwares /opt is similar to c:\Program Files.
8. \bin
it contains commands used by all users (Binary Files).
9. \sbin
9. \sbin
it contains commands used by only super user (ROOT)(super user binary files).
10. \dev
10. \dev
it contains device files like /dev/had -for hard drives,/dev/cd-rom -for
cd drives /dev similar to device manager of windows.
11. \proc
cd drives /dev similar to device manager of windows.
11. \proc
it contain process files,the contents are not permanent,they keep
changing it also calles as Virtual Directory.its file contain useful
information used by OS like /proc/meminfo..information of RAM/SWAP
/proc/cpuinfo-information of CPU.
/var it contains variables data like mails,log files.
12. \mnt
changing it also calles as Virtual Directory.its file contain useful
information used by OS like /proc/meminfo..information of RAM/SWAP
/proc/cpuinfo-information of CPU.
/var it contains variables data like mails,log files.
12. \mnt
it is default mount points for any partition.it is empty by default.
13. \media
13. \media
it contains all of removable media like CD-ROM,pendrive.
14. \lib
14. \lib
it contains library files which are used by OS library files in linux
are SO(shared objects)files /lib is similar to .dll files of windows.
are SO(shared objects)files /lib is similar to .dll files of windows.
BASIC COMMANDS
1 cat > filename
To create a file
2
cat filename
To display the content of the file
3
cat >> filename
To append the data in the already existing file
4
touch file1 file2 file3
Creating multiple files at same time using touch command
5
ls
Directory listing
6
ls -a
list all files including hidden file starting with '.'
7
ls --color
colored list
8
ls -d
list directories - with ' */'
9
ls -F
add one char of */=>@| to enteries
10
ls -i
list file's inode index number
11
ls -l
list with long format - show permissions
12
ls -la
list long format including hidden files
13
ls -lh
list long format with readable file size
14
ls -ls
list with long format with file size
15
ls -r
list in reverse order
16
ls -R
list recursively directory tree
17
ls -s
list file size
18
ls -S
sort by file size
19
ls -t
sort by time & date
20
ls -X
sort by extension name
21
mkdir dirname
To Creating a Directory
22
mkdir –p dirname/{file1/{subfile1,subfile2},file2/{subfile1,subfile2},file3 /{subfile1,subfile2}}
Making multiple directories inside a directory
22
cp file1 dirname
Copying files into directory
23
cp –rvfp dirname2 dirname
Copying directories from one location to other
24
mv file2 dirname
Moving files from one location to other (cut and Paste)
25
mv dirname dirname2
Moving a Directory from one location to other
26
mv file1 linuxfile
Renaming a File
27
mv dirname linuxdir
Renaming a Directory
28
rm filename
or
rm –f filename (without prompting)
Removing a File
29
rmdir dirname
Removing an Empty directory
30
ln -s file link
Create symbolic link link to file
31
more file1
Output the contents of the file
32
head file1
Output the first 10 lines of the file
33
tail file1
Output the last 10 lines of the file
34
tail -f file1
Output the contents of file as it grows,starting with
the last 10 lines
35
touch file1
Create or update file
36
cd directoryname
Change to directory
37
cd ..
Change to previous directory
38
clear
The clear command clears the screen and wipes the board clean
39
man ftp
With the man command, you can retrieve the information in the manual and display it as text output on your screen
To create a file
2
cat filename
To display the content of the file
3
cat >> filename
To append the data in the already existing file
4
touch file1 file2 file3
Creating multiple files at same time using touch command
5
ls
Directory listing
6
ls -a
list all files including hidden file starting with '.'
7
ls --color
colored list
8
ls -d
list directories - with ' */'
9
ls -F
add one char of */=>@| to enteries
10
ls -i
list file's inode index number
11
ls -l
list with long format - show permissions
12
ls -la
list long format including hidden files
13
ls -lh
list long format with readable file size
14
ls -ls
list with long format with file size
15
ls -r
list in reverse order
16
ls -R
list recursively directory tree
17
ls -s
list file size
18
ls -S
sort by file size
19
ls -t
sort by time & date
20
ls -X
sort by extension name
21
mkdir dirname
To Creating a Directory
22
mkdir –p dirname/{file1/{subfile1,subfile2},file2/{subfile1,subfile2},file3 /{subfile1,subfile2}}
Making multiple directories inside a directory
22
cp file1 dirname
Copying files into directory
23
cp –rvfp dirname2 dirname
Copying directories from one location to other
24
mv file2 dirname
Moving files from one location to other (cut and Paste)
25
mv dirname dirname2
Moving a Directory from one location to other
26
mv file1 linuxfile
Renaming a File
27
mv dirname linuxdir
Renaming a Directory
28
rm filename
or
rm –f filename (without prompting)
Removing a File
29
rmdir dirname
Removing an Empty directory
30
ln -s file link
Create symbolic link link to file
31
more file1
Output the contents of the file
32
head file1
Output the first 10 lines of the file
33
tail file1
Output the last 10 lines of the file
34
tail -f file1
Output the contents of file as it grows,starting with
the last 10 lines
35
touch file1
Create or update file
36
cd directoryname
Change to directory
37
cd ..
Change to previous directory
38
clear
The clear command clears the screen and wipes the board clean
39
man ftp
With the man command, you can retrieve the information in the manual and display it as text output on your screen
FILE PERMISSION COMMANDS
1
#chmod ugo=rwx filename
Assigning full permission to the file i.e. rwx to all
2
#chmod u=rwx,g=rw,o=r myfile
Assigning different permissions to the file (user=rwx, group=rw and others=r)
3
#chmod ugo=rwx filename
Assigning full permission to the file i.e. rwx to all
2
#chmod u=rwx,g=rw,o=r myfile
Assigning different permissions to the file (user=rwx, group=rw and others=r)
3
#chmod 764 myfile (where 7 means rwx i.e. 4+2+1, rw=6 i.e. 4+2 and 1 indicates x)
Assigning different permissions to the file (user=rwx, group=rw and others=r)
4
#chmod 777 myfile
Assigning full permission to the file i.e. rwx to all
5
#chmod 770 myfile (where 0 indicates no permissions)
Removing all permissions from others
PROCESS MANAGEMENT
1
#ps
The ps command gives the running process of the present terminal and present command.
2
#ps –a
To see all the active processes running on the terminal
3
#ps –u
To see the processes running by the logged in user (ex root)
4
#ps -x
To see which process are attached with some terminals (tty) and which are not
5
#ps –G or #pgrep –G
To see which process are running by a particular group
6
#ps –aux
To see the offline process of the system, already executed
7
#kill –l
To see list of signals
8
#kill signalno processid
To kill the signal
9
#top
To monitor all processes in the system use the following command
10
#bg
List stopped or background jobs,resume a stopped job in the background
SYSTEM INFORMATION
1
#df
show the disk usage
2
#du
show directory space usage
3
#free
show memory and swap usage
4
#whereis app
show possible locations of app
5
#which app
show which applications will be run by default
6
#date
show the current date and time
7
#cal
show this month's calender
8
#uptime
show current uptime
9
#whoami
who you are logged in as
10
#finger user
display information about user
11
#uname -a
show kernel information
12
#cat /proc/cpuinfo
cpu information
13
#cat proc/meminfo
memory information
14
#man
show the manual for command
15
#w
display who is online
FILE COMPRESSION
1
#tar xf file.tar
Extract the files from file.tar
2
#tar cf file.tar file
Create tar named file.tar containing file
3
#tar czf file.tar.gz files
Create a tar with Gzip compression
4
#tar xzf file.tar.gz
Extract a tar using Gzip
5
#tar cjf file.tar.bz2
Create tar with Bzip2 compression
6
#tar xjf file.tar.bz2
Extract a tar using Bzip2
7
#gzip file
Compresses file and renames it to file.gz
8
#gzip -d file.gz
Decompresses file.gz back to file
NETWORK COMMANDS
1
#dig -x host
Reverse lookup host
2
#wget file
Download file
3
#wget -c file
Continue a stopped download
4
#ping host
Ping host and output results
5
#whois domain
Get whois information for domains
6
#dig domain
Get DNS information for domain
7
#hostname
Display the hostname
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