Ключевой частью ответа Сандро является звонок на indent-rigidly
.
C-x TAB (translated from C-x <tab>) runs the command indent-rigidly,
which is an interactive compiled Lisp function in `indent.el'.
It is bound to C-x TAB.
(indent-rigidly start end arg)
Indent all lines starting in the region sideways by arg columns.
Called from a program, takes three arguments, start, end and arg.
You can remove all indentation from a region by giving a large negative arg.
Итак, отметьте регион, введите числовой аргумент, нажмите C-x TAB
.