[PATCH tig 1/2] Document how to use pipes and redirection with 'bind'

[Wolfram Sang <wsa@kernel.org>]

When my bind command using a pipe did not work, I grepped through the
docs for 'pipe' and 'redirection' with no results. Only after I found
out in the issues tracker that it was intentional, then I noticed the
solution in the examples, too.

Add a paragraph to make it more explicit.

Signed-off-by: Wolfram Sang <wsa@kernel.org>
---
 doc/tigrc.5.adoc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/doc/tigrc.5.adoc b/doc/tigrc.5.adoc
index 630e8f6..1aa8085 100644
--- a/doc/tigrc.5.adoc
+++ b/doc/tigrc.5.adoc
@@ -690,6 +690,9 @@ console output shown (as if '!' was specified). When multiple command options
 are specified their behavior are combined, e.g. "?<git commit" will prompt the
 user whether to execute the command and will exit Tig after completion.
 
+Note that if you want to use pipes or redirection in your commands then you
+must run them in a subshell, i.e. embed your commands in `sh -c '<commands>'`.
+
 Browsing state variables
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
-- 
2.20.1