$ mv file.text !#:1:r.txt evaluates to: $ mv file.text file.txt (colon separated) !# means this command 1 is the position of the argument to be modif

$ mv file.text !#:1:r.txt evaluates to: $ mv file.text file.txt (colon separated) !# means this command 1 is the position of the argument to be modified r means strip extension There's tons of history modifiers and a lot to be learned reading `man bash`.