We already saw how to hide a file inside another using SilentEye and now we will see how to do the same through the terminal.
The advantage of this method is that we are not forced to use a specific extension for the final result as it happens with SilentEye, besides that it is more comfortable for me.
1- We take the file that we want to hide and compress it. Let's suppose it's called hidden_file.rar.
2- We look for an image (we will call it img_original.jpg) and put it in the same folder as hidden_file.rar.
3- Now we open a terminal and put.
$ cd /home/usuario/ruta_de_la_carpeta
$ cat img_original.jpg fichero_oculto.rar > img_falsa.jpg
4- If we execute img_falsa.jpg we will see the image perfectly img_original.jpg, but if you look, the size is larger than the original.
Now to see the hidden file, we just have to rename img_falsa.jpgBy img_falsa.rar and unzip it.
Please note: I tried compressing the hidden file in .tar and the trick didn't work for me.