Thanks for the idea, I have pushed the attached patch to make this clearer.
From ed3d6e2d30a96f58102908cf55a42c962a82de0c Mon Sep 17 00:00:00 2001 From: James Youngman <j...@gnu.org> 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: findutils-patc...@gnu.org
* 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
