3.5.7 Word Splitting
The shell scans the results of parameter expansion, command substitution,
and arithmetic expansion that did not occur within double quotes for
The shell treats each character of
as a delimiter, and splits the results of the other
expansions into words on these characters. If
IFS is unset, or its value is exactly
the default, then any sequence of
characters serves to delimit words. If
has a value other than the default, then sequences of
the whitespace characters
are ignored at the beginning and end of the
word, as long as the whitespace character is in the
IFS whitespace character).
Any character in
IFS that is not
whitespace, along with any adjacent
whitespace characters, delimits a field. A sequence of
whitespace characters is also treated as a delimiter.
If the value of
IFS is null, no word splitting occurs.
Explicit null arguments (
") are retained.
Unquoted implicit null arguments, resulting from the expansion of
parameters that have no values, are removed.
If a parameter with no value is expanded within double quotes, a
null argument results and is retained.
Note that if no expansion occurs, no splitting