Tell the world how to convert gigabytes to bytes with units(1) easily

It turns out that units(1) is not as horrible to use in scripts
as I initially thought. When the --terse flag is combined
with an appropriate output format (set via --output-format),
units(1) is actually capable of producing very nice results.
For example:

    units -o %0.f -t '4 gigabytes' bytes

is is just going to print out the expected value of 4294967296.

There is no time to waste. People have to know about it.

I am adding an example for this at the top of the examples section
because this is what users are most likely looking for.

Approved by:	bcr (mentor)
Differential Revision:	https://reviews.freebsd.org/D24096
This commit is contained in:
0mp 2020-03-17 10:02:59 +00:00
parent 0aabba20a1
commit c45c4bfe6a

View File

@ -1,5 +1,5 @@
.\" $FreeBSD$
.Dd February 3, 2020
.Dd March 17, 2020
.Dt UNITS 1
.Os
.Sh NAME
@ -232,7 +232,20 @@ The standard units file.
.Ex -std
.Sh EXAMPLES
.Bl -tag -width 0n
.It Sy Example 1 : No Interactive usage
.It Sy Example 1 : No Simple conversion of units
.Pp
This example shows how to do simple conversions, for example from gigabytes
to bytes:
.Bd -literal -offset 2n
.Li $ Ic units -o %0.f -t '4 gigabytes' bytes
4294967296
.Ed
.Pp
The
.Fl o Cm %0.f
part of the command is required to print the result in a non-scientific
notation (e.g, 4294967296 instead of 4.29497e+09).
.It Sy Example 2 : No Interactive usage
.Pp
Here is an example of an interactive session where the user is prompted for
units:
@ -261,7 +274,7 @@ units:
.Li You want : Ic degC
29.444444
.Ed
.It Sy Example 2 : No Difference between Do Ic \&| Dc No and Do Ic / Dc No division
.It Sy Example 3 : No Difference between Do Ic \&| Dc No and Do Ic / Dc No division
.Pp
The following command shows how to convert half a meter to centimeters.
.Bd -literal -offset 2n
@ -293,7 +306,7 @@ as
.Dq Ic 0.5/meter ,
which is not conformable to
.Dq Ic cm .
.It Sy Example 3 : No Simple units file
.It Sy Example 4 : No Simple units file
Here is an example of a short units file that defines some basic
units:
.Pp
@ -307,7 +320,7 @@ units:
.It "ft 12 inches"
.It "mile 5280 ft"
.El
.It Sy Example 4 : No Viewing units and conversions of the default units file
.It Sy Example 5 : No Viewing units and conversions of the default units file
The following shell one-liner allows the user to view the contents of the
default units file:
.Bd -literal -offset 2n