of the `--diff-filter` option on what the status letters mean.
--submodule[=<format>]::
- Specify how differences in submodules are shown. When `--submodule`
- or `--submodule=log` is given, the 'log' format is used. This format lists
- the commits in the range like linkgit:git-submodule[1] `summary` does.
- Omitting the `--submodule` option or specifying `--submodule=short`,
- uses the 'short' format. This format just shows the names of the commits
- at the beginning and end of the range. Can be tweaked via the
- `diff.submodule` configuration variable.
+ Specify how differences in submodules are shown. When specifying
+ `--submodule=short` the 'short' format is used. This format just
+ shows the names of the commits at the beginning and end of the range.
+ When `--submodule` or `--submodule=log` is specified, the 'log'
+ format is used. This format lists the commits in the range like
+ linkgit:git-submodule[1] `summary` does. When `--submodule=diff`
+ is specified, the 'diff' format is used. This format shows an
+ inline diff of the changes in the submodule contents between the
+ commit range. Defaults to `diff.submodule` or the 'short' format
+ if the config option is unset.
--color[=<when>]::
Show colored diff.
--no-prefix::
Do not show any source or destination prefix.
+--line-prefix=<prefix>::
+ Prepend an additional prefix to every line of output.
+
For more detailed explanation on these common options, see also
linkgit:gitdiffcore[7].