domingo, 21 de janeiro de 2024

Linux Command Line Hackery Series: Part 1




In this concise article we will learn some basics of how to use Linux Command line, so lets get started.

Requirements:

1. An open Terminal in your Linux Box. I'm using Kali Linux 2.0
or you can check out this amazing website Webminal

 Command:  ls
Syntax:         ls [flag(s)]
Function:      ls is short for list. ls command is used to list the contents of a directory these contents include files, folders, and links. ls has many optional flags as well, some of them are described below
Flags:    -a this flag is used to view hidden files that is those files whose names are preceded                      by a '.'(dot)
               -l  this flag is used to view file permissions, owner of the file, group of the owner, the                        file size, the modification date, and the filename. We'll talk more about it in later                            articles.

 Command:  mkdir
Syntax:         mkdir dirname
Function:      mkdir is used to create a directory (or a folder) with the name which is followed by the command

 now lets create a directory in our current directory named as myfiles, how would you do that?

 mkdir myfiles

 which command should we use in order to verify that the directory has been created in our current folder?

 ls

 this will list all the files and directories in our current folder. Do you see myfiles directory listed?

 Command:  cd
Syntax:         cd path/to/directory
Function:      cd is short for change directory. It is used to navigate directories, or to make it clear it does the same thing as what double clicking on a folder do except it doesn't show you contents of the directory :(. In order to navigate or visit another directory we need to provide it's ABSOLUTE-PATH or RELATIVE-PATH you heard that, didn't ya?

 Paths are of two types relative path or absolute path (also called full-path). Relative as the name suggests is relative to the current directory, so if you have to navigate to a folder within the current directory you'll just simply type cd directory_name. But what if you have to navigate to a directory which is the parent of current directory? Well it's easy just type cd .. (yes double dots, you noticed that .. and . thing when you typed ls -a, didn't you?). The double dots mean the directory above current directory (i,e the parent directory) and a single dot means the current directory (i,e the directory that I'm currently in). Now if you have to navigate two directories above current directory using relative path navigation you'll type

 cd ../.. 

 here .. means previous directory and another .. after slash (/) means the previous directory of the previous directory sounds confusing..!

 The Absolute Path means full path to the file or folder which starts from root directory. Say I want to navigate to my home folder using absolute path, then I'll type:

 cd /home/user

 where user is the username
Now think of navigating to the myfiles folder from your home directory using the absolute path, it will be something like this:

 cd /home/user/myfiles

 Exercise: Create a directory project1 inside your home directory and inside the project1 directory create a file and a directory named index.html and css respectively. Then navigate to the css directory and create a style.css file inside it. At last navigate out of the css directory to home both using the relative and absolute path mechanisms.

 [Trick: To get quickly out of any directory to your home directory type cd ~ [press Enter] or simply cd [press Enter]]

 Command:  touch
Syntax:         touch filename
Function:      touch is a nifty little function used to create an empty file (actually it's used to change access time of a file but everyone has got bad habits :P ). You can create any type of empty file with the touch command. If you are a bit curious about touch read the manual page of the touch command using the man touch command.

 Now lets create a few files inside of our myfiles directory

 touch file1 file2 file3

 The above command creates three empty files in our current directory named file1, file2, and file3.
How will you verify that it has indeed created these three files in your current directory? I won't answer this time.

 Command:  echo
Syntax:         echo Hacker manufacturing under process
Function:      echo is used to display a line of text. By default echo displays a line of text on the terminal which is the standard output device (stdout for short). However we can redirect the output of an echo command to a file using > (the greater than symbol).
Now if we have to echo a line of text to a file, say file1 in our myfiles directory, we will type:

 echo This is file1 > file1

 The above command will echo the text "This is file1" to file1.

 Command:  cat
Syntax:         cat filename [anotherfilename...]
Function:      cat stands for concatenate (not that puny little creature in your house). The main function of cat is to concatenate files and display them on your terminal (or in geeky terms stdout). But its also used to display the contents of a file on your terminal.

 Let's display the contents of file1 in the myfiles directory that we echoed to it using the echo command, for that we'll type:

 cat file1

 Awesome I can see on black screen contents of my file (what if your terminals background is white?), looks like I'm becoming a hacker. In case you don't see it then I suggest you should give up the thought of becoming a hacker. Just kidding you might have missed a step or two from the above steps that we performed.

 Now lets say that we want to add another line of text to our file using the echo command should we use the same greater than (>) symbol? No, if we want to add another line (which in geeky terms is to append a line) to our file using the echo command we have to use >> (two greater than symbols) like this:

 echo Another line of text >> file1

 now to check the contents of file1 we'll type:

 cat file1

 OK we wrote two lines inside of the file1.
Does it mean we have to add three greater than symbols to write third line? Oh! I didn't thought you'd be such a genius.

 A single greater than symbol (>) means redirect the output of the preceding command to a file specified after the > symbol. If the file exists then overwrite everything that's in it with the new contents and if the file does not exist then create one and write to it the output of the preceding command. So if you had typed

 echo Another line of text > file1

 it would have overwritten the contents of the file1 with "Another line of text" and the line "This is file1" would no longer be present in the file.

 Two greater than symbols (>>) mean that append (remember the geeky term?) the output of the previous command to the end of file specified after >>. Now if you want to add another line of text to file1, you won't use >>> rather you'll use >> like this:

 echo Third line in file1 >> file1

 This is it for today. But don't worry we'll learn more things soon.

Related links


Publicada por à(s)

Sem comentários:

Enviar um comentário

Subscrever: Enviar feedback (Atom)

Quando eu te falei em amor

Quando os meus olhos te tocaram
Eu senti que encontrara
A outra, metade de mim
Tive medo de acordar
Como se vivesse um sonho
Que não pensei em realizar
E a força do desejo
Faz me chegar perto de ti

Quando eu te falei em amor
Tu sorriste para mim
E o mundo ficou bem melhor
Quando eu te falei em amor
Nos sentimos os dois
Que o amanha vem depois
E não no fim

Estas linhas que hoje escrevo
São do livro da memória
Do que eu sinto por ti
E tudo o que tu me das
É parte da história que eu ainda não vivi
E a força do desejo
Faz me chegar de ti

Quando eu te falei em amor
Tu sorriste para mim
E o mundo ficou bem melhor
Quando eu te falei em amor
Nos sentimos os dois
Que o amanha vem depois e não no fim

André Sardet

Collide

The dawn is breaking
A light shining through
You're barely waking
And I'm tangled up in you
Yeah

But I'm open, you're closed
Where I follow, you'll go
I worry I won't see your face
Light up again

Even the best fall down sometimes
Even the wrong words seem to rhyme
Out of the doubt that fills my mind
I somehow find, you and I collide

I'm quiet, you know
You make a first impression
I've found I'm scared to know
I'm always on your mind

Even the best fall down sometimes
Even the stars refuse to shine
Out of the back you fall in time
I somehow find, you and I collide

Don't stop here
I've lost my place
I'm close behind

Even the best fall down sometimes
Even the wrong words seem to rhyme
Out of the doubt that fills your mind

You finally find, you and I collide
You finally find You and I collide
You finally findYou and I collide

Howie Day


Everything

You're a falling star, You're the get away
car.
You're the line in the sand when I go too
far.
You're the swimming pool, on an August day.
And You're the perfect thing to see.

And you play it coy, but it's kinda cute.
Ah, When you smile at me you know exactly what you
do.
Baby don't pretend, that you don't know it's
true.
Cause you can see it when I look at you.

And in this crazy life, and through these crazy
times
It's you, it's you, You make me sing.
You're every line, you're every word, you're
everything.

You're a carousel, you're a wishing well,
And you light me up, when you ring my bell.
You're a mystery, you're from outer space,
You're every minute of my everyday.

And I can't believe, uh that I'm your man,
And I get to kiss you baby just because I
can.
Whatever comes our way, ah we'll see it
through,
And you know that's what our love can do.

And in this crazy life, and through these crazy
times
It's you, it's you, You make me sing
You're every line, you're every word, you're
everything.

So, La, La, La, La, La, La, La
So, La, La, La, La, La, La, La

And in this crazy life, and through these crazy
times
It's you, it's you, You make me sing.
You're every line, you're every word, you're
everything.
You're every song, and I sing along.
Cause you're my everything.
yeah, yeah

So, La, La, La, La, La, La, La
So, La, La, La, La, La, La, La

Michael Bublé