# 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
`""`).

[**Again note:**]{.underline} 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)
-   [WordSplitting](http://mywiki.wooledge.org/WordSplitting),
    [IFS](http://mywiki.wooledge.org/IFS), and
    [DontReadLinesWithFor](http://mywiki.wooledge.org/DontReadLinesWithFor) -
    Greg's wiki