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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Masami Hiramatsu' <mhiramat@kernel.org>
CC:     Shuah Khan <shuah@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
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        Li Philip <philip.li@intel.com>,
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        Xiao Yang <yangx.jy@cn.fujitsu.com>,
        Andreas Schwab <schwab@linux-m68k.org>
Subject: RE: [PATCH v2] selftests/ftrace: Use printf for backslash included
 command
Thread-Topic: [PATCH v2] selftests/ftrace: Use printf for backslash included
 command
Thread-Index: AQHWJ5lrSXqvrVhCTk6tpfgbVx7YuKii+RAg
Date:   Mon, 11 May 2020 14:59:20 +0000
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        <158920418730.16156.8299185499520876735.stgit@devnote2>
 <20200511223804.9483cab03c9221818ff4fc5b@kernel.org>
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> > +    pos=$(printf "%s" "${2%^*}" | wc -c) # error position
> > +    command=$(printf "%s" "$2" | tr -d ^)

You may want to put all the $(...) inside "" to avoid field splitting
(not relevant to a shell assignment with modern shells) and
filename globbing.

> >      echo "Test command: $command"
> >      echo > error_log
> > -    (! echo "$command" >> "$3" ) 2> /dev/null
> > +    (! printf "%s" "$command" >> "$3" ) 2> /dev/null

WTF is the (! for ??
The (...) is a subshell.
And ! inverts the exit status.
Neither is needed at all.

	David

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