REFERENCE:

Webmin Installation:https://www.tecmint.com/install-webmin-on-ubuntu/
NOTE: after installation login with your username/root and terminal password.

Difference between apt Vs apt-get:

 Main diff is apt-get uses in 2016 versions of Linux and apt is newer version.
 Apt shows dependencies which are required to be upgrade and apt-get don’t.

COMMANDS
update and upgrade software: sudo apt update && upgrade

1. +tab: create auto when you write half letters of the dir/file/commands
Example: cd Des+tab it will auto write cd Desktop.
Example: ls+tab shows all commands which are using “ls” keywords.

2. Chmod:
0=No permission
1=x
2=w
3=xw
 4=r
5=rx
6=rw
7=rwx
Give permission: chmod 777 filename OR chmod u=rwx,g=r,o= filename
Modify permission: chmod u+rwx,g+rwx,o+rwxc
Remove permission: chmod 000 filename OR chmod u-rwx, g-rwx, o-wrx filename
3. umask: If want to change permission (which are default when created file/dir). use 0000
Example: umask 0022. First 0 is by default and second zero means user have xrw permission and
group/other have rx permission in dir, just USER:0-7=7 GROUP:OTHER:7-2=5 which rx for group
and other in dir.

Default Dir umask is 0775

Now Dir umask is 114

Because 7-6=1 for u and g
5-2=3 for other.

For file it subtract with 666 because by default linux nerver give execute permission to a file
because file may be contain viruses. So user have rw permission and group/other have r permission.
Default File umask is 664

4. Chown: Change the ownership.

Example: chown umair file.txt.

5. open/xdg-open: Open any file/dir GUI (open command maybe only applicable for ubuntu
22.04).
6. Alias: convert long command into short.
Example: alias dir="ls -l | awk '{print \$9}'"

7. file: give file type

8. wc: use to show file line word and characters
NOTE: First will be a line, second will be a word and last will be a character
l: line
w: word
c: character

9. pwd: reveals current path.

10. cd -: go to the last directory you were in and reveals the path.

11. >: print/store command’s output. But it overwrite a text you can also use >> which append
a text.
 12. tac:

13. tr:

14. fmt:

15. nl:

16. strace:

17. dtrace:

18. ftrace:

19. copy splits file content: cat file1 file2 > file3

20. split combined file: split -l 1(how many lines) file3

21. cal: shows calendar

22. date: shows date

23. ln: It create link between files. There are two type of link 1)Hard and 2) soft links.
Hard link: It creates replica of a file.
Example: ln file.txt file_ln.txt.
Soft link: It creates shortcut of a file.
Example: ln -s file.txt file_ln.txt.
NOTE: soft link will not work if original will delete.

24. touch: To make files

25. mkdir -p: To make directories inside directories

26. Rename dir: mv -T current_name new_name

27. rm: Remove files -rf is used when dir/file is not delete.

NOTE: r means recursive means it will also perform in sub dir as well.

28. rmdir: Remove dir

29. cp: copy file and dir.

Example: cp test.txt /home/umair/Desktop

30. mv: Move file and dir

Example: mv text /home/umair/Desktop

31. history: Show all commands which were previously fired.

32. man: Manual to show which short key is use for that command

Example: man uname

33. ls -la: listing with permission and all file (which are hide show as .)
l: show permission:
a: show hide file which start dot.

COMPRESSING FILE:
34. Tar:

35. gzip:

36. gunzip:

37. compress:

38. uncompress:

PRINT FILE:
39. cat: shows text inside a file. And -n shows text inside a file with numbers.

40. echo: print a file in terminal.

41. sort: print file in a sort form -n for -u for unique etc.

42. uniq: only print unique values.

43. head or head -50: shows start 10 lines

44. tail or tail -20: shows last 10 lines

45. sed: Help to print range in a file.

sed -n ‘num1p,num2p’ file_name

46. cut: Cut any character or word from any file or command.

-c: cut character. ‘-’ use for range and ‘,’ use for particular character number.
 -f: cut by field (we can not use this option without range)

-d: define the range etc . , space or anything.

47. aw

k:

Advance of cut command when there are many spaces cut can not perform task.

Syntax: awk ‘{print $column_number1,$column_number2}’

NOTE: Work only for spaces.

Syntax: awk -F’:’ ‘{print $column_number1,$column_number2}’

F: for range

48. les

s:

Display file content page by page.

49. more: Display file content page by page.

NOTE: To go to next page press space and want to line by line press enter.
NOTE: The main difference is that less can go previous page(just press upper arrow key) where as
more can not.
50. zgrep: Print patterns inside a zip file.
51. grep(Global regular expression print): find a text in a file & print it.

 ^ (means beginning in every command): will print beginning patterns only.

grep “^umair khan” /etc/passwd

 $ (means ending in every command): will print end patterns only.

 -i: ignore case sensitive

 -w: print exact word

 -n (number): print line number

 -c (count): print total line number in the form of number.

 -v (invert match): print unmatched pattern.

 -o: print that word only.

 -A2: print 2 lines after matched patterns.

 -b2: // // before 2 lines

 -C2: print 2 lines before and after matched patterns.

 -R/rgrep (Recursive): If you do not know exact path.

 -E/egrep (Extended): Grep can not pint multiple patterns at the same time. Egrep is use

for that. OR

egrep ‘name1|name2|name3’ path.

NOTE: if use -E in grep command, It will perform as egrep.

NETWORK:
52. ifconfig: Interface-configuration, to check device name and change the configuration of a
device.
ifconfig down/up: if want to down/up any device
Example: ifconfig docker0 down
Change ip/net-mask/broadcast: ifconfig device_name IP/net mask/broadcast
Example: ifconfig docker0 192.168.0.1
Example: ifconfig docker0 netmask/broadcast 255.255.255.255
NOTE: Want to change all using single command
Example: ifconfig docker0 192.168.0.1 netmask 255.255.255.255 broadcast 192.168.42.255
ether: It's show mac address of the device. If want to change it.
Example: ifconfig docker0 hw ether AA:1F:0A:DD:FE
hw: hardware
NOTE: you can give multiple alias IP to a device using docker0:0 and so on.…

53. Dig:

54. ping:

55. iptable:

56. netstat: shows all current network connections

57. nslookup: Use to detail about domain and DNS records.

58. nmap:

59. tcpdump:

60. mtr:

61. traceroute:

62. dig airman:

63. airodump:
PROCESSES:
64. ps: Shows current processes

65. top: Shows all processes

66. Htop:

67. atop:

68. lsof: List of output file. It is use to find out which file is open or which file is dependent to
whom.
lsof -u user_name | more for particular user. -i for network only -i 4 and -i 6 for ipv4 or
ipv6 only.
A memory-mapped file contains the contents of a file in virtual memory.

File descriptor
Current working dir
Memory mapping files
Inode number of dir

Link/path

Read and write

Read
Write

First in first out

NOTE: press f after command will show all shorts forms with their full name.

69. kill: kill processes

NOTE: If process not is not killing use -9.
Example: kill -9 2424

SYSTEMS:
70. Go to server using ip: ssh name@ip then password.
Example: ssh root@206.130.120.44 pK&FgL347@0r
71. cpu: lscpu

72. uname: Shows system information.

 73. ram: free -h

74. disk: lsblk

75. sudo cat /etc/shadow: Shows all user’s password in encrypted form.

76. cat

Encrypted password

Users

/etc/passwd: Shows all user’s.

Search user umair: grep umair /etc/passwd

GECOS or the full name of the user. This field contains a list of comma-separated values with the
following information:
 User’s full name or the application name.
 Room number.
 Work phone number.
 Home phone number.
 Other contact information.

77. list all hardware: lshw

78. ios release and version: cat etc/os-release

79. whoami: show user name.

80. last: show all logins.

81. hostname: show machine host name

82. hostnamectl set-hostname new_name: Change hostname.

83. df -h: Use to show partition size and how much it is used and which dir it is mount

84. du -h: Use to show all file/dir size

85. nmon: Shows all detail about system in one click.

86. iostat:

87. sar:

SEARCH COMMANDS:
88. whereis: find path of a file

89. which: searches current $PATH for executable

90. Find: to find file or dir etc.

Example: find / -type f -name umair.txt Or find / -type d -name umair.txt

NOTE: iname use to find case sensitive and type d means directory only and f is for file.
If don't know exact name.
find / -type f -iname "*.php"

91. Locate: same as find command but fast.

Example: locate -ic umair.txt

i: shows only case sensitive file dir
c: count how many files are.
NOTE: It uses updatedb to search file/dir. When you create or delete file you should run updatedb
command.