PARAMETERS
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PARAMETERS
A
parameter
is an entity that stores values.
It can be a
.IR name ,
a number, or one of the special characters listed below under
.BR "Special Parameters" .
For the shell's purposes, a
variable
is a parameter denoted by a
.IR name .
A parameter is set if it has been assigned a value. The null string is
a valid value. Once a variable is set, it may be unset only by using
the
unset
builtin command (see
.SM
SHELL BUILTIN COMMANDS
below).
A
variable
may be assigned to by a statement of the form
If
value
is not given, the variable is assigned the null string. All
values
undergo tilde expansion, parameter and variable expansion,
command substitution, arithmetic expansion, and quote
removal (see
.SM
EXPANSION
below). If the variable has its
integer
attribute set (see
declare
below in
.SM
.BR "SHELL BUILTIN COMMANDS" )
then
value
is subject to arithmetic expansion even if the $((...)) expansion is
not used (see
"Arithmetic Expansion"
below).
Word splitting is not performed, with the exception
of "$@"\fP as explained below under
.BR "Special Parameters" .
Pathname expansion is not performed.
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