List of TCP and UDP port numbers

1 TCP Port Service Multiplexer (TCPMUX)
5 Remote Job Entry (RJE)
7 ECHO
18 Message Send Protocol (MSP)
20 FTP -- Data
21 FTP -- Control
22 SSH Remote Login Protocol
23 Telnet
25 Simple Mail Transfer Protocol (SMTP)
29 MSG ICP
37 Time
42 Host Name Server (Nameserv)
43 WhoIs
49 Login Host Protocol (Login)
53 Domain Name System (DNS)
69 Trivial File Transfer Protocol (TFTP)
70 Gopher Services
79 Finger
80 HTTP
103 X.400 Standard
108 SNA Gateway Access Server
109 POP2
110 POP3
115 Simple File Transfer Protocol (SFTP)
118 SQL Services
119 Newsgroup (NNTP)
137 NetBIOS Name Service
139 NetBIOS Datagram Service
143 Interim Mail Access Protocol (IMAP)
150 NetBIOS Session Service
156 SQL Server
161 SNMP
179 Border Gateway Protocol (BGP)
190 Gateway Access Control Protocol (GACP)
194 Internet Relay Chat (IRC)
197 Directory Location Service (DLS)
389 Lightweight Directory Access Protocol (LDAP)
396 Novell Netware over IP
443 HTTPS
444 Simple Network Paging Protocol (SNPP)
445 Microsoft-DS
458 Apple QuickTime
546 DHCP Client
547 DHCP Server
563 SNEWS
569 MSN
1080 Socks

For more details: https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

Shell - Linux structure

Application programs: Mail-FTP-DBMS, etc...

Shell: Interaction btw user and OS.

Kernel: Hearth of OS. Bridge btween hardware and user interface. I/O, processes

Hardware: CPU-GPU-Harddisk-etc. physicall

*-----

We can access to the shell via terminal. Terminal is not the shell, just a kind of emulator...

to see version of the shell type below command on terminal;

echo $SHELL

to see kernel;

uname

for more information regarding kernel;

uname - a

Linux commands

command -parameter+argument

touch --> creates a file(touch afile)

echo linux > afile --> type a text to target file

cat -->shows the content of the mentioned file(cat afile)

echo dontoverwrite >> afile (> overwrites, >> does not overwrite)

head --> first 8 rows

tail --> last 8 rows

more --> read line by line by pressing enter(press Ctrl+C to break more)

pwd --> where I am exactly?

ls --> shows the content of the folder you are in

ls - ln --> shows the content of the entire directory with the permission rights

cd --> jump upper level

cd +arg --> jump to folder arg


mkdir +arg --> creates a new folder named arg


rmdir +arg --> deletes the folder arg(same as command: rm)

cp --> copy a file(cp sourceFile targetFileWithNewName)
cp -r --> copy a folder(cp -r sourceFolder targetFolderWithNewName)

mv --> cut a file(mv file targetFolder)
mv --> addition of cur functionality, also changes the name of a file(mv file newName)

find --> search function. (find Folder)

locate  --> same as find command.

man --> manual for the commands(man grep)

help --> similar with the man.(grep --help)

grep --> find for a spesific pattern in a file
touch grepsample
echo test > grepsample
echo test2 >> grepsample
cat grepsample
cat grepsample | grep 2


useradd -m -g groupname -G othergroupnames -s shell username --> add new user
useradd -m -g users -G audio, video -s /bin/bash lorem

cat /etc/group --> shows user groups


ls - ln --> shows the content of the entire directory with the permission rights

chmod -7 fileName  --> Removes the rights for the current user
chmod -77 fileName --> Removes the rights for the current user group
chmod -777 fileName --> Removes the rights for the others

chmod +7 fileName  --> Gives rights for the current user
chmod +77 fileName --> Gives rights for the current user group

chmod +777 fileName --> Gives rights for the others

1 = execute, 2 = write, 4 = read, 7 total

ps aux --> whole active processes
ps -au(userName) --> active processes for the userName

ps -aux | grep processName --> active processes list which contaion processName

kill -9 processId --> kills process 

killall processName --> kills all processes 

.deb packages

dpkg -i packageName --> install package
dpkg -r packageName --> remove package
dpkg -l --> show installed packages


apt installer

apt update --> updates the package list from repositories
apt apgrade --> upgrades whole packages in your local
apt search packageName --> searchs a package from repository
apt install packageName --> installs a package

apt remove packageName --> removes a package

add apt repository repName --> adds a repository


*---

df --> displays harddisk configurations
fdisk -arg --> harddisk configurations

free --> ram
cat /proc/meminfo --> ram snapshot

vmstat --> CPU
top --> CPU with more details


*---

netstat

netstat -t --> list of tcp connections
netstat -u --> list of udp connections
netstat --route --> route table, gateway, genmask
netstat -s --> network statistics

ifconfig --> network details, ip address, mac, etc.