How to create a file in Linux from terminal window?

Depending on what you want the file to contain:

• touch /path/to/file for an empty file

• somecommand > /path/to/file for a file containing the output of some command.

    eg: grep --help > randomtext.txt
        echo "This is some text" > randomtext.txt
  

• nano /path/to/file or vi /path/to/file (or any other editor emacs,gedit etc)
  It either opens the existing one for editing or creates & opens the empty file to enter, if it doesn't exist

Use touch

touch filename