Linux Basics

Hey buddy i am using Linux as my OS . this notes containing the basics of linux commands , service , tools , configurations & many more.....

Linux Filesystem

In kali linux there are different files in " / " root directory each of them contains different types of files..


 • /bin      # basic programs (ls, cd, cat, etc.)
 • /sbin    # system programs (fdisk, mkfs, sysctl, etc)
 • /etc     # configuration files like "paswd, shadow , hosts, crontab"
 • /tmp     # temporary files (typically deleted on boot)
 • /usr/bin   # applications (apt, ncat, nmap, etc.)
 • /usr/share   # application support and data files

There are many other directory present as well , but these are some of basics and important directory that we should look before move in.

Basic Linux Commands

Its important that we know basics commands of linux because 95% of the time we spend in terminal or shell .

i am running as root, so i didn't user sudo before any command. if you are using low priv account make sure to use sudo.

Man page

man page is a manual for any command we used, we can read about their switches and descriptions about that commands eg. ( man ls )


man passwd    # show the uses of password command

man -k passwd # -k  search for keyword (like apropos) , show possible command related with passwd 

apropos passwd  # apropos will search possible list of man page for a possible match based on keyword.

Listing Files


ls

ls /usr/share/wordlists/*    # display all items in wordlists dir , we use *  wildcard.

ls -la    # -l for listing format  and -a for hidden 

ls -R     # recursive search

Moving Around


pwd         # print the current working directory.

cd /        # go to root directory where all files start.

cd ~        # go to users home directory.

cd /usr/share/wordlist     # we change the directory to wordlist .

cd ..        # go one directory back and now we are at "share".

cd -     # same use go back one directory.

Creating Directory

while making directory remember linux is case sensitive.


mkdir notes        # it will create a directory named as "notes"

mkdir new notes     # it will create two new directory new and notes 

mkdir "new notes"    # it will create one new dir "new notes"

rmdir notes     # it will remove notes dir

rm -rf notes     # it will remove notes forcefully


mkdir "new dir"    # it will create new dir named as "new dir"

cd new\ dir/    # now we are in "new dir" dir, here \  backslash is used for ignoring the empity space b/q new and dir .

mkdir -p notes{maths,phy,chem}    # here it create dir notes and inside it create 3 new dir named as maths , phy ,chem .

Finding Files in kali system

which

which $PATH     # it will show the path environment for given name

which python     # show the dir where python is present

locate


sudo updatedb     # update the databse before running the commands.

locate *.nse    # find all files with .nse extension 

locate sbd.exe    # find file sbd.exe

find
- Find is very use-full command when it comes to finding file with different parameters, read man page for find command.


find / -name *.sbd    # it will find the file form / dir with name *.sbd .

find / -perm -u=s -type f 2>/dev/null    # find file form / dir with -perm permisson , -u=s denotes look for files that are owned by the root user -type is type f denote looking for regular files , 2 denotes stander error redirected to /dev/null

Managing kali Services

kali comes with default Pre-installed services such as ssh , http, mysql etc.
we can use this services according with our's need.

SSH Service

we can use systemctl or service command for running and stopping the services.


systemctl start ssh     # running the ssh    

systemctl status ssh     # status of ssh

systemctl stop ssh    # stoping 

service ssh start     # same as previous 

systemctl enable ssh     # if we want that ssh automatic start with boot then we enable the service with enable switch , same as disable

example

 
                                                                                                                                                                                                                                                                   
┌──(root💀rio)-[~]
└─# service ssh start    
                                                                                                                                      
┌──(root💀rio)-[~]
└─# service ssh status
● ssh.service - OpenBSD Secure Shell server
     Loaded: loaded (/lib/systemd/system/ssh.service; disabled; vendor preset: disabled)
     Active: active (running) since Tue 2022-08-09 06:18:32 IST; 4s ago
       Docs: man:sshd(8)
             man:sshd_config(5)
    Process: 98046 ExecStartPre=/usr/sbin/sshd -t (code=exited, status=0/SUCCESS)
   Main PID: 98047 (sshd)
      Tasks: 1 (limit: 14118)
     Memory: 1.5M
        CPU: 23ms
     CGroup: /system.slice/ssh.service
             └─98047 "sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups"

Aug 09 06:18:32 rio systemd[1]: Starting OpenBSD Secure Shell server...
Aug 09 06:18:32 rio sshd[98047]: Server listening on 0.0.0.0 port 22.
Aug 09 06:18:32 rio sshd[98047]: Server listening on :: port 22.
Aug 09 06:18:32 rio systemd[1]: Started OpenBSD Secure Shell server.
                                                                                                                                      
┌──(root💀rio)-[~]
└─# ss -antlp | grep sshd             
LISTEN 0      128               0.0.0.0:22        0.0.0.0:*    users:(("sshd",pid=98047,fd=3))
LISTEN 0      128                  [::]:22           [::]:*    users:(("sshd",pid=98047,fd=4))
                                                                                                                                      
┌──(root💀rio)-[~]
└─# service ssh stop

HTTP Service

it can be run as systemctl or service command.
same goes to enable and disable.
HTTP Service is a web server that loads at port 80 on our local-host IP its dir is /var/www/html where it host.
apache is a webserver that comes pre-installed in kali so we are using apache , we can user nginx or python as well.
we can use it as a web-server for downloading files at Victum Machine.

# for apache
service apache2 start 
service apache2 status
service apache2 stop

systemctl start apache2    # for start
systemctl enable apache2    # for enable, it will automatic start afte every reboot
systemctl stop apache2        # for stop
systemctl disable apache2        # for changing conf. of apache

systemctl list-unit-files    # for checking the list of enable & diable services..

# for nginx
service nginx start 
service nginx stop

example


┌──(root💀rio)-[~]
└─# service apache2 start 
                                                                                                                                      
┌──(root💀rio)-[~]
└─# service apache2 status
● apache2.service - The Apache HTTP Server
     Loaded: loaded (/lib/systemd/system/apache2.service; disabled; vendor preset: disabled)
     Active: active (running) since Tue 2022-08-09 06:37:07 IST; 5s ago
       Docs: https://httpd.apache.org/docs/2.4/
    Process: 98385 ExecStart=/usr/sbin/apachectl start (code=exited, status=0/SUCCESS)
   Main PID: 98402 (apache2)
      Tasks: 6 (limit: 14118)
     Memory: 18.5M
        CPU: 95ms
     CGroup: /system.slice/apache2.service
             ├─98402 /usr/sbin/apache2 -k start
             ├─98404 /usr/sbin/apache2 -k start
             ├─98405 /usr/sbin/apache2 -k start
             ├─98406 /usr/sbin/apache2 -k start
             ├─98407 /usr/sbin/apache2 -k start
             └─98408 /usr/sbin/apache2 -k start

Aug 09 06:37:07 rio systemd[1]: Starting The Apache HTTP Server...
Aug 09 06:37:07 rio apachectl[98401]: AH00558: apache2: Could not reliably determine the server's fully qualified domain name, using >
Aug 09 06:37:07 rio systemd[1]: Started The Apache HTTP Server.
                                                                                                                                      
┌──(root💀rio)-[~]
└─# service apache2 stop

Searching, Installing, and removing Tools

apt update

apt update command will update the list of available packages, including information related to their versions, descriptions, etc so that we can upgrade the system.

apt update

apt upgrade

After the APT database has been updated, we can upgrade the installed packages and core system to the latest versions using the apt upgrade command.

apt upgrade -y     # upgrade the full package

apt upgrade metsaploit-framework    # upgrade single package

apt-cache and apt show

The apt-cache search command displays much of the information stored in the internal cached package database.
apt show display the information of the package

apt-cache search pure-ftpd

apt show pure-ftpd

example

┌──(root💀rio)-[~]
└─# apt-cache search pure-ftpd
ftpd - File Transfer Protocol (FTP) server
mysqmail-pure-ftpd-logger - real-time logging system in MySQL - Pure-FTPd traffic-logger
pure-ftpd - Secure and efficient FTP server
pure-ftpd-common - Pure-FTPd FTP server (Common Files)
pure-ftpd-ldap - Secure and efficient FTP server with LDAP user authentication
pure-ftpd-mysql - Secure and efficient FTP server with MySQL user authentication
pure-ftpd-postgresql - Secure and efficient FTP server with PostgreSQL user authentication
resource-agents - Cluster Resource Agents
                                                                                                                                      
┌──(root💀rio)-[~]
└─# apt show pure-ftpd        
Package: pure-ftpd
Version: 1.0.50-2.1+b2
Priority: optional
Section: net
Source: pure-ftpd (1.0.50-2.1)
Maintainer: Stefan Hornburg (Racke) <racke@linuxia.de>
Installed-Size: 670 kB
Provides: ftp-server
Depends: lsb-base (>= 3.2-14), openbsd-inetd | inet-superserver, pure-ftpd-common (= 1.0.50-2.1), libc6 (>= 2.33), libcap2 (>= 1:2.10), libcrypt1 (>= 1:4.1.0), libpam0g (>= 0.99.7.1), libsodium23 (>= 1.0.10), libssl3 (>= 3.0.0)
Conflicts: ftp-server
Replaces: ftp-server
Homepage: https://www.pureftpd.org/project/pure-ftpd/
Tag: interface::daemon, network::server, protocol::ftp, protocol::ssl,
 role::program, works-with::file
Download-Size: 173 kB
APT-Sources: https://mirror.anigil.com/kali kali-rolling/main amd64 Packages
Description: Secure and efficient FTP server
 Free, secure, production-quality and standard-conformant FTP server.
 Features include chrooted home directories,
 virtual domains, built-in 'ls', anti-warez system, configurable ports for
 passive downloads, FXP protocol, bandwidth throttling, ratios,
 fortune files, Apache-like log files, fast standalone mode, atomic uploads,
 text / HTML / XML real-time status report, virtual users, virtual quotas,
 privilege separation, SSL/TLS and more.

apt install

apt install will install the package

apt install pure-ftpd    # install package pure-ftpd

apt-remove --purge

apt remove pure-ftpd    # remove this package 

apt purge --purge pure-ftpd    # this option remove the package with no leftover.

dpkg

dpkg used to install offline package

dpkg -i  man-db_2.7.0.2-5_amd64.deb    # -i install this package 

dpkg -r man-db_2.7.0.2-5_amd64.deb     # -r remove the package

misc commands


who                  # show users info in details
whoami            # show your current user
uname -a    # display kernal information
         
su kali                   # for swithching to kali user
su root                  # for switching root user
adduser jhon        # it wiil add user like jhon
su jhon                 # for switching to jhon user
deluser jhon         # it will del user jhon 

sudo shutdown now -r         #  for restsrt
sudo shutdown now -c         #  cancel the previous shoutdown
sudo shutdown now            #  system shutdown
poweroff                     # power off system
poweroff -f                  # forcefully
reboot                       # reboot system 
reboot -f                    # forcefully

date                                    # display date 
date --set ='10 Feb 2017 11:13'         #  for change date
cal                                     # for  calander

yes              # it will loop 
yes sahil        # loop sahil   ,  [ctrl] + c       to terminate

factor 1024            # helps to do maths factor

Searching, Installing, and Removing tools

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Last updated 2 years ago