# Linux Command Intro

Catatan ini ditujukan untuk mempermudah pencarian perintah-perintah dasar Linux untuk keperluan Pentesting/VA.Cheatsheet ini disadur dari akun Github rekan saya[ Satrya Mahardhika](https://github.com/mahaardhiika/VAPT-Training/).

## whoami

Print active User ID

```bash
whoami
```

## pwd

Print Working directory

```bash
pwd
```

## mkdir

Make Directory

```bash
mkdir pentest/
```

## cd

Change directory

```bash
cd pentest // Change directory to pentest (Inside Working Directory)
cd /var // change directory to var (Outside Working Directory)
cd //Back to home Directory
cd .. // Directory Up
```

## ls

List files in working Directory

```bash
ls
ls -la // Print out all files including hidden files
```

## which

Locate executable file full path

```bash
which nmap // Locate the full path of nmap  
```

## man

Manual Page of a Command

```bash
man which // Manual page of which Command
man -K "change password" // Search for command to change password
```

## locate

Find / Search for files

```bash
locate -i passwd // Find for passwd files with case-Insensitive
```

## wget

Download a file

```bash
wget http://<IP>:<Port>/access_log.txt
```

## cat

Concatenate / print contents of a files

```bash
cat access_log.txt
```

## head

Cat only first 10 lines of a file

```bash
head access_log.txt
```

## tail

Cat only last 10 lines of a file

```bash
less access_log.txt
```

## cp

Copy file

```bash
cp access_log.txt access_log.txt.backup
```

## mv

Rename or cut a file

```bash
mv access_log.txt exercise.txt
```

## grep

Search for specific word in a file

```bash
grep admin exercise.txt
```

## wc

Count lines, words, bytes, of a files

```bash
wc exercise.txt
```

## sort

Sort files

```bash
sort -u exercise.txt // Sort unique lines on exercise.txt
```

## tab completion

Automatically fill the command/files names we write

```bash
cat ex<TAB> // will show exercise.txt
```

## history

Check history of command we input

```bash
history
```

## sudo

Super User do!

```bash
cat /etc/shadow // It will prompt Access Denied
ls -la /etc/shadow // Check permission of /etc/shadow file
whoami
sudo -l // Check our sudo privilege
sudo /etc/shadow
cat /etc/shadow
sudo !! // Sudo above command
```

## su

switch user

```bash
su kali // Switch to kali
sudo su // Switch to root
```

## Piping & Redirection

Piping ( | ) is a command that let you use two or more commands such that output of one command serves as input to the next command.

```bash
cat exercise.txt // Will show all lines of exercises.txt
cat exercise.txt | grep admin // will only show line contain admin
cat exercise.txt | grep admin | wc -c // Count bytes of above output
```

Redirection is change the output of command to a files

```bash
cat exercise.txt | grep admin > admin_exercise.txt
echo "This will overwrite" > admin_exercise.txt | Overwrite exercise.txt with "This will overwrite", or make exercise.txt file if it is not exists
echo "This will not overwrite" >> admin_exercise.txt | write "This will not overwrite" to the last line of exercise.txt
```

## cut

Cutting out some section of a file

```bash
cat user.txt | cut -d ":" -f 1 //Menampilkan hanya colomn 1
```

## awk

More powerful than Cut

```bash
cat user.txt | awk -F ":" '{print $1 $2}'
cut user.txt | awk -F ":" '{print "Terdapat user bernama " $1}'
```