Minimum HTTP server with netcat

Problem

Sometimes you need to have a simple HTTP server. You want to check connectivity from other machine or whatever sinister reason you can have.

Solution

We are going to create a simple HTTP server at port 8000.
You can use the netcat command:

nc -l -p 8000 -c 'echo -e "HTTP/1.1 200 OK\n\nHello $(id -un)\nCurrent time $(date)"

Then you can go to a web browser and write load the url at the port 8000

http://localhost:8000

But this works just for one connection, after that connection you must execute again the nc command, so to accept more connections you must add a while loop:

while [ 1 ];do nc -l -p 8000 -c 'echo -e "HTTP/1.1 200 OK\n\nHello $(id -un)\nCurrent time $(date)"'; done

May be you want to display a simple html file (with no images, ajax or any other HTML element that launchs more HTTP requests) like this one:

<!DOCTYPE html>
<html>
<body>
<h1>Example</h1>
This is a simple<br/>
webserver running with
<b>nc</b>
</body>
</html>

Let’s suppose that you have your html saved in a file called index.html, then you can show it in your netcat server as follows:

while [ 1 ];do nc -l -p 8000 -c 'echo -e "HTTP/1.1 200 OK\n";cat index.html'; done

If you are not able to connect to your netcat server may be you have activated iptables, take a look writing as root:

iptables -L

If you want to remove the iptables that can be blocking this requests write the following commands as root:

iptables -F
iptables -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT

Replace content of multiple files

Problem

Imagine you have some misspelled words in some documents:

$ grep Intalac *
file02.html: <h2 align="left"><a name="ubuntu"></a>Intalación en Ubuntu 12.10<img src="img/009-ubuntu.png" width="62" height="59"></h2>
file04.html: <h3 align="left">Intalación en Ubuntu <img src="img/009-ubuntu.png" width="62" height="59"></h3>
file04.html: <h3 align="left">Intalación en Ubuntu <img src="img/009-ubuntu.png" width="62" height="59"></h3>

In this case you want to change a word in all the documents.

Solution

You can use sed with vi commands:

sed -i 's/<original>/<replaced>/g' 

In this case we can solve the problem with

sed -i 's/Intal/Instal/g' *.html