# Word splitting

FIXME to be continued!

Word splitting occurs once any of the following expansions are done (and
only then!)

- [Parameter expansion](/syntax/pe.md)
- [Command substitution](/syntax/expansion/cmdsubst.md)
- [Arithmetic expansion](/syntax/expansion/arith.md)

Bash will scan the results of these expansions for special `IFS`
characters that mark word boundaries. This is only done on results that
are **not double-quoted**!

## Internal Field Separator IFS

The `IFS` variable holds the characters that Bash sees as word
boundaries in this step. The default contains the characters

- \<space\>
- \<tab\>
- \<newline\>

These characters are also assumed when IFS is **unset**. When `IFS` is
**empty** (nullstring), no word splitting is performed at all.

## Behaviour

The results of the expansions mentioned above are scanned for
`IFS`-characters. If **one or more** (in a sequence) of them is found,
the expansion result is split at these positions into multiple words.

This doesn't happen when the expansion results were **double-quoted**.

When a null-string (e.g., something that before expanded to
\>\>nothing\<\<) is found, it is removed, unless it is quoted (`''` or
`""`).

<u>**Again note:**</u> Without any expansion beforehand, Bash won't
perform word splitting! In this case, the initial token parsing is
solely responsible.

## See also

- [Introduction to expansion and substitution](/syntax/expansion/intro.md)
- [Quoting and escaping](/syntax/quoting.md)