From ed3d6e2d30a96f58102908cf55a42c962a82de0c Mon Sep 17 00:00:00 2001
From: James Youngman <address@hidden>
Date: Tue, 5 Jan 2016 18:08:03 +0000
Subject: [PATCH] find: point out more clearly that -a has a higher precendence
 than -o.
To: address@hidden

* find/find.1 (OPERATORS): Point out that -o has lower precendence
than -a, even when the -a is implicit.
(NON-BUGS): Explain the same thing here.
---
 find/find.1 | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/find/find.1 b/find/find.1
index 2f2c974..cb6e7a8 100644
--- a/find/find.1
+++ b/find/find.1
@@ -1546,6 +1546,17 @@ hierarchy only once.  The
 .B \-fprintf
 action can be used to list the various matched items into several
 different output files.
+.P
+Please note that
+.B \-a
+when specified implicitly (for example by two tests appearing without
+an explicit operator between them) or explicitly has higher precedence
+than
+.BR \-o .
+This means that
+.B find . \-name afile \-o \-name bfile \-print
+will never print
+.IR afile .
 
 
 .SH UNUSUAL FILENAMES
@@ -2172,10 +2183,25 @@ syntax had been deprecated since findutils-4.2.21
 which was released in 2005.
 .P
 .SH "NON-BUGS"
+.SS Operator precedence surprises
+The command
+.B find . \-name afile \-o \-name bfile \-print
+will never print
+.I afile
+because this is actually equivalent to
+.BR "find . \-name afile \-o \e( \-name bfile \-a \-print \e)" .
+Remember that the precedence of
+.B \-a
+is higher than that of
+.B \-o
+and when there is no operator specified between tests,
+.B \-a
+is assumed.
+.SS \(lqpaths must precede expression\(rq error message
 .nf
 .B $ find . \-name *.c \-print
 find: paths must precede expression
-Usage: find [\-H] [\-L] [\-P] [\-Olevel] [\-D help|tree|search|stat|rates|opt|exec] [path...] [expression]
+Usage: find [\-H] [\-L] [\-P] [\-Olevel] [\-D ... [path...] [expression]
 .fi
 .P
 This happens because
@@ -2185,9 +2211,9 @@ resulting in
 .B find
 actually receiving a command line like this:
 .nf
-
+.
 .B find . \-name bigram.c code.c frcode.c locate.c \-print
-
+.
 .fi
 That command is of course not going to work.  Instead of doing things
 this way, you should enclose the pattern in quotes or escape the wildcard:
-- 
2.1.4