I write before guide, howto create file on Linux shell / command line without text editor (with cat command) and this is guick tip howto display / show file contents (tabs, line-breaks, non-printing characters (ASCII control characters: octal 000 – 037)) and display all on Linux shell / command line. This is very useful when you want to know the entire contents of the file. Example file I use /tmp/testing.
This is a very typical case, the need to create a temp file on the command line quickly. Opening editor, writing content, save file and quit editor is not the fastest possible way. A faster way is to use the cat command with the name of the file and write contents of the file and give the end-of-file character (Ctrl-D). This is guide, howto create (or append to) text file without text editor on Linux shell / command line.