numfmt Man page

NUMFMT(1) User Commands NUMFMT(1)


numfmt – Convert numbers from/to human-readable strings


numfmt [OPTION]… [NUMBER]…


Reformat NUMBER(s), or the numbers from standard input if none are

Mandatory arguments to long options are mandatory for short options

print warnings about invalid input

-d, –delimiter=X
use X instead of whitespace for field delimiter

replace the numbers in these input fields (default=1) see FIELDS

use printf style floating-point FORMAT; see FORMAT below for

auto-scale input numbers to UNITs; default is ‘none’; see UNIT

specify the input unit size (instead of the default 1)

use locale-defined grouping of digits, e.g. 1,000,000 (which
means it has no effect in the C/POSIX locale)

–header[=N] print (without converting) the first N header lines; N defaults
to 1 if not specified

failure mode for invalid numbers: MODE can be: abort (default),
fail, warn, ignore

pad the output to N characters; positive N will right-align;
negative N will left-align; padding is ignored if the output is
wider than N; the default is to automatically pad if a white‐
space is found

use METHOD for rounding when scaling; METHOD can be: up, down,
from-zero (default), towards-zero, nearest

add SUFFIX to output numbers, and accept optional SUFFIX in
input numbers

auto-scale output numbers to UNITs; see UNIT below

the output unit size (instead of the default 1)

-z, –zero-terminated
line delimiter is NUL, not newline

–help display this help and exit

output version information and exit

UNIT options:
none no auto-scaling is done; suffixes will trigger an error

auto accept optional single/two letter suffix:

1K = 1000, 1Ki = 1024, 1M = 1000000, 1Mi = 1048576,

si accept optional single letter suffix:

1K = 1000, 1M = 1000000, …

iec accept optional single letter suffix:

1K = 1024, 1M = 1048576, …

iec-i accept optional two-letter suffix:

1Ki = 1024, 1Mi = 1048576, …

FIELDS supports cut style field ranges:
N N’th field, counted from 1

N- from N’th field, to end of line

N-M from N’th to M’th field (inclusive)

-M from first to M’th field (inclusive)

– all fields

Multiple fields/ranges can be separated with commas

FORMAT must be suitable for printing one floating-point argument ‘%f’.
Optional quote (%’f) will enable –grouping (if supported by current
locale). Optional width value (%10f) will pad output. Optional zero
(%010f) width will zero pad the number. Optional negative values
(%-10f) will left align. Optional precision (%.1f) will override the
input determined precision.

Exit status is 0 if all input numbers were successfully converted. By
default, numfmt will stop at the first conversion error with exit sta‐
tus 2. With –invalid=’fail’ a warning is printed for each conversion
error and the exit status is 2. With –invalid=’warn’ each conversion
error is diagnosed, but the exit status is 0. With –invalid=’ignore’
conversion errors are not diagnosed and the exit status is 0.

$ numfmt –to=si 1000

-> “1.0K”

$ numfmt –to=iec 2048

-> “2.0K”

$ numfmt –to=iec-i 4096

-> “4.0Ki”

$ echo 1K | numfmt –from=si

-> “1000”

$ echo 1K | numfmt –from=iec

-> “1024”

$ df -B1 | numfmt –header –field 2-4 –to=si
$ ls -l | numfmt –header –field 5 –to=iec
$ ls -lh | numfmt –header –field 5 –from=iec –padding=10
$ ls -lh | numfmt –header –field 5 –from=iec –format %10f


Written by Assaf Gordon.


GNU coreutils online help:
Report numfmt translation bugs to


Copyright © 2016 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


Full documentation at:
or available locally via: info ‘(coreutils) numfmt invocation’

GNU coreutils 8.25 February 2016 NUMFMT(1)

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