NUMFMT(1) General Commands Manual NUMFMT(1)

numfmt - Convert numbers from/to human-readable strings

numfmt [OPTION]... [NUMBER]...

Convert numbers from/to human-readable strings

print warnings about invalid input
use locale-defined grouping of digits, for example 1,000,000 (which means it has no effect in the C/POSIX locale)
use X instead of whitespace for field delimiter
replace the numbers in these input fields; see FIELDS below
use printf style floating-point FORMAT; see FORMAT below for details
auto-scale input numbers to UNITs; see UNIT below
specify the input unit size
auto-scale output numbers to UNITs; see UNIT below
the output unit size
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 whitespace is found
print (without converting) the first N header lines; N defaults to 1 if not specified
use METHOD for rounding when scaling

Possible values:

  • up
  • down
  • from-zero
  • towards-zero
  • nearest
print SUFFIX after each formatted number, and accept inputs optionally ending with SUFFIX
use STRING to separate the number from any unit when printing; by default, no separator is used
set the failure mode for invalid input

Possible values:

  • abort
  • fail
  • warn
  • ignore
line delimiter is NUL, not newline
Print help
Print version

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.

v(uutils coreutils) 0.11.0

2026-09-01