2.1 KiB
Introduction
The command line interface is run in a terminal (or prompt). It is the direct interface with your computer. There you are able to do the same things are you are able in a graphic interface such as visiting a folder, reading and writing files.
But the command line interface allows you access to a number of other programs which are really useful in a developer's every day life or while participating in CTFs. You should not be an expert, but with little knowledge of the command line you will already be able to do a number of things faster and quicker.
Terminals in Linux and OSX are quite similar, if you run Windows, things are a bit different.
Understanding paths
Paths are the base of the structure of your operating system. You have to think of it like a tree (there is even a command to show you the whole structure of your folders called tree -- try it out!).
For example:
home folder
| sub folder
| | sub sub folder
| | file in sub sub folder.txt
| second sub folder
Your home folder (/home/your_username) is usually abreaviated by ~. So for example the "Documents" folder in your home folder is marked as ~/Documents. This is how the structure works for the example above:
home folder/sub folder/sub sub folder/file in sub sub folder.txt
Basic command line
- List the files in the current folder:
ls - See where you are:
pwd - See who you are:
whoami - Go in a folder:
cd INSERT_HERE_THE_NAME_OF_YOUR_FOLDER - Go in the parent folder:
cd .. - Go to your home directory:
cd ~orcd - Print a file in the terminal:
cat THE_NAME_OF_YOUR_FILE - Copy a file:
cp YOUR_FILE YOUR_DESTINATION
Run programs in command line
You can feel like a real hacker from movies while just using your terminal. So this means you can run program in the command line. Already the few examples above are small programs. To run a program you have to write the name of the program you want to run and options and then press "enter" to run it.
Many programs have a manual to explain how to use them, you can access it by using the --help or -h option. Try typing: cat --help and then press enter in your terminal.