NUMFMT(1) User Commands NUMFMT(1)
NAME
numfmt - Convert numbers from/to human-readable strings
SYNOPSIS
numfmt [OPTION]... [NUMBER]...
DESCRIPTION
Reformat NUMBER(s), or the numbers from standard input if none are
specified.
Mandatory arguments to long options are mandatory for short options
too.
--debug
print warnings about invalid input
-d, --delimiter=X
use X instead of whitespace for field delimiter
--field=FIELDS
replace the numbers in these input fields (default=1); see
FIELDS below
--format=FORMAT
use printf style floating-point FORMAT; see FORMAT below for de-
tails
--from=UNIT
auto-scale input numbers to UNITs; default is 'none'; see UNIT
below
--from-unit=N
specify the input unit size (instead of the default 1)
--grouping
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
--invalid=MODE
failure mode for invalid numbers: MODE can be: abort (default),
fail, warn, ignore
--padding=N
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
--round=METHOD
use METHOD for rounding when scaling; METHOD can be: up, down,
from-zero (default), towards-zero, nearest
--suffix=SUFFIX
add SUFFIX to output numbers, and accept optional SUFFIX in in-
put numbers
--to=UNIT
auto-scale output numbers to UNITs; see UNIT below
--to-unit=N
the output unit size (instead of the default 1)
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
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(1) 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.
EXAMPLES
$ 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
AUTHOR
Written by Assaf Gordon.
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
COPYRIGHT
Copyright © 2023 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/numfmt>
or available locally via: info '(coreutils) numfmt invocation'
GNU coreutils 9.4 June 2025 NUMFMT(1)
Generated by dwww version 1.16 on Sun Jul 12 06:51:04 CEST 2026.