how to remove all unneeded characters from a .txt file?(only keep letters and numbers)

[ub3rl337z4ur]

I need an automatic system. There are a lot of special characters that all need to be removed from more than 1 file.

 

[Alabalcho]

Hire a programmer to write an application for you. Or learn little bit about "sed" command-line utility and how to install it under Windows (warning: this is not point-and-click task!!!)

 

[aznricepuff]

If you are under windows, install cygwin: https://www.cygwin.com/

Then open up the cygwin terminal and use the following command:

for f in *.txt; do sed 's/[^[:alnum:]]//g' "$f"; done

This loops through all files with a .txt extension in the current directory and deletes all non-alphanumeric characters. If you want to preserve whitespace as well:

for f in *.txt; do sed 's/[^[:alnum:][:space:]]//g' "$f"; done