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Full Discussion: Variable scope in bash
Top Forums Shell Programming and Scripting Variable scope in bash Post 302589325 by Corona688 on Wednesday 11th of January 2012 10:11:52 AM
Old 01-11-2012
The execution is slow because you're running dozens of externals in backticks all the time. You should use externals to process big batches of data -- not individual lines. Externals are fast enough on bulk data, but overkill for anything less, like makng 10 phone calls to say 10 words. Most of your script could probably be done with one execution of awk, if we knew the details.

If you show the input you get from sar, and the output you want from the script, we can find a much more efficient way to do so, probably in nearly pure awk. It can do much more than '{ print $1 }'

I don't see anything obviously wrong with your script, though there's many places in it where things are unquoted and quoting may be important.
 

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LEARN ABOUT MOJAVE

sleep

SLEEP(1)						    BSD General Commands Manual 						  SLEEP(1)

NAME

     sleep -- suspend execution for an interval of time

SYNOPSIS

     sleep seconds

DESCRIPTION

     The sleep command suspends execution for a minimum of seconds.

     If the sleep command receives a signal, it takes the standard action.

IMPLEMENTATION NOTES

     The SIGALRM signal is not handled specially by this implementation.

     The sleep command will accept and honor a non-integer number of specified seconds (with a '.' character as a decimal point).  This is a non-
     portable extension, and its use will nearly guarantee that a shell script will not execute properly on another system.

EXIT STATUS

     The sleep utility exits 0 on success, and >0 if an error occurs.

EXAMPLES

     To schedule the execution of a command for x number seconds later (with csh(1)):

	   (sleep 1800; sh command_file >& errors)&

     This incantation would wait a half hour before running the script command_file.  (See the at(1) utility.)

     To reiteratively run a command (with the csh(1)):

	   while (1)
		   if (! -r zzz.rawdata) then
			   sleep 300
		   else
			   foreach i (`ls *.rawdata`)
				   sleep 70
				   awk -f collapse_data $i >> results
			   end
			   break
		   endif
	   end

     The scenario for a script such as this might be: a program currently running is taking longer than expected to process a series of files, and
     it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata
     is created).  The script checks every five minutes for the file zzz.rawdata, when the file is found, then another portion processing is done
     courteously by sleeping for 70 seconds in between each awk job.

SEE ALSO

     nanosleep(2), sleep(3)

STANDARDS

     The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

HISTORY

     A sleep command appeared in Version 4 AT&T UNIX.

BSD
								  April 18, 1994							       BSD
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