.\" SPDX-License-Identifier: 0BSD
.\"
.Dd
.Dt TR 1
.Os
.
.Sh NAME
.Nm tr
.Nd transliterate bytes
.
.Sh OPTIONS
.Ss SET EXPANSION
In all places where an arbitrary character is allowed, it can instead be one of the following escapes:
.Bl -tag -compact -offset 4n -width ".Sy \e\e , \ea , \eb , \et"
.It Sy \e\e , \ea , \eb , \et
.It Sy \en , \ev , \ef , \er
The backslash, bell, backspace, tab, line feed, vertical tab, form feed, and carriage return characters, respectively.
.
.It Sy \e Ns Ar O Ns Op Ar O Ns Op Ar O
Octal byte of value.
.
.It Sy \e Ns Ar c
Literal
.Ar c ,
without considering any other sequences.
.El
.Pp
Additionally, the following expansions are recognised:
.
.Bl -tag -offset 4n -width ".Sy [\& Ns Ar c Ns Sy *] , [\& Ns Ar c Ns Sy * Ns Ar len Ns Sy \&]"
.It Ar f Ns Sy - Ns Ar t
Inclusive range of all characters between
.Ar f
and
.Ar t ,
in ascending order.
Recognised only if
.Ar t
is at least
.Ar f .
.
.It Sy [: Ns Ar class Ns Sy :]
Where
.Ar class
may be any of
.Bl -tag -compact -offset 2n -width ".Sy xdigit"
.It Sy alnum
alphanumeric characters
.It Sy alpha
letters
.It Sy blank
blanks
.It Sy cntrl
control characters
.It Sy digit
digits
.It Sy graph
graphic characters \(em printable except space
.It Sy lower
lower-case letters
.It Sy print
printable characters
.It Sy punct
punctuation characters
.It Sy space
whitespace
.It Sy upper
upper-case letters
.It Sy xdigit
hexadecimal digits
.El
These correspond directly to respective
.Pp
.St -p1003.1-2008
only guarantees equivalent relative ordering for
.Sy [:lower:]
and
.Sy [:upper:] ,
so reliance upon any given ordering of characters generated by character classes may not be portable.
.
.It Sy [= Ns Ar e Ns Sy =]
Just
.Ar e .
.St -p1003.1-2008
specifies this to be characters with the same equivalence (collation) class as
.Ar e
according to the current locale, but this is scarcely supported and most implementations just do
.Ar e .
.
.It Sy [\& Ns Ar c Ns Sy *] , [\& Ns Ar c Ns Sy * Ns Ar len Ns Sy \&]
If
.Ar len
is
.Em 0
or missing, repeat
.Ar c
until length of set matches length of the first set (not available when expanding the first set), otherwise repeat
.Ar c len
times.
.Ar len
is a decimal integer
.Pq octal if it starts with Sy 0 .
.El
.Pp
If enabled,
.Fl c
occurs directly after processing these transformations.