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Full Discussion: eval in shell scripting
Top Forums Shell Programming and Scripting eval in shell scripting Post 302197548 by mobydick on Wednesday 21st of May 2008 07:00:02 AM
Old 05-21-2008
eval in shell scripting

what is the real usage of eval in shell scripting

whats the difference between
$ cmd

&&
eval cmd
 

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TRACE-CMD-START(1)														TRACE-CMD-START(1)

NAME
trace-cmd-start - start the Ftrace Linux kernel tracer without recording SYNOPSIS
trace-cmd start [OPTIONS] DESCRIPTION
The trace-cmd(1) start enables all the Ftrace tracing the same way trace-cmd-record(1) does. The difference is that it does not run threads to create a trace.dat file. This is useful just to enable Ftrace and you are only interested in the trace after some event has occurred and the trace is stopped. Then the trace can be read straight from the Ftrace pseudo file system or can be extracted with trace-cmd-extract(1). OPTIONS
The options are the same as trace-cmd-record(1), except that it does not take options specific to recording (-s, -o, -F, -N, and -t). SEE ALSO
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-stop(1), trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-split(1), trace-cmd-list(1), trace-cmd-listen(1) AUTHOR
Written by Steven Rostedt, <rostedt@goodmis.org[1]> RESOURCES
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git COPYING
Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL). NOTES
1. rostedt@goodmis.org mailto:rostedt@goodmis.org 06/11/2014 TRACE-CMD-START(1)
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