How to reformat numbers in Bash.
$ n=1023555
$ m=$(numfmt --to=si n)
$ echo $m
1.1M
Other options
--to=none # no scaling. Output: 1023555
--to=si # International System of Units (SI) standard. Output 1.1M
--to=iec # International Electrotechnical Commission (IEC) standard. Output: 1.1Mi
--to=iec-i # International Electrotechnical Commission (IEC) standard. Output: 1.1M
--to=auto # ‘auto’ can only be used with --from.