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Top Forums UNIX for Dummies Questions & Answers While read issue... Post 302173856 by giannicello on Saturday 8th of March 2008 11:57:02 AM
Old 03-08-2008
It does sound crazy and not logical but that's what I experienced.

If I were to build on your example, what happens if you got to count '2' in your first while and you want to pull all '2's from your input file "countfile" (i.e grep '2' into another temp file) and process that temp file in the inner while?

I noticed in my situation that the inner while will pull only the second, third, fourth, etc. occurrence of '2' from countfile...and when it processes the temp file, it will do it once and go break out. This is on aix with ksh.

My work around was to duplicate the countfile into say countfile2 and grep for all '2' from countfile2 inside the inner while, then it processed all the records as expected and returned to the next record of the countfile.
In this example, '2' is simplistic but in my example, it's a table column name. I'm grepping for all records with this column so I can do some more processing with these columns. In my case, I could duplicate the file and it's small enough, but if it's a large file, it wouldn't be ideal to have two identical files just to handle a while issue...

I admit it's weird and not logical but I know I've encountered it before a few times in the past. My solution was always to switch to a 'for loop' with inner while. However, this time, I need the while loop in a while since I have way more variables to deal with then just a 'for x in... ' loop.

Gianni
 

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LEARN ABOUT PHP

break

break(1)                                                           User Commands                                                          break(1)

NAME

       break, continue - shell built-in functions to escape from or advance within a controlling while, for, foreach, or until  loop

SYNOPSIS

   sh
       break [n]

       continue [n]

   csh
       break

       continue

   ksh
       *break [n]

       *continue [n]

DESCRIPTION

   sh
       The break utility exits from the enclosing for or while loop, if any. If n is specified, break n levels.

       The continue utility resumes the next iteration of the enclosing for or while loop. If n is specified, resume at the n-th enclosing loop.

   csh
       The  break  utility  resumes  execution after the end of the nearest enclosing foreach or while loop. The remaining commands on the current
       line are executed. This allows multilevel breaks to be written as a list of break commands, all on one line.

       The continue utility continues execution of the next iteration of the nearest enclosing while or foreach loop.

   ksh
       The break utility exits from the enclosed for, while, until, or select loop, if any. If n is specified,  then  break  n  levels.  If  n  is
       greater than the number of enclosing loops, the outermost enclosing loop shall be exited.

       The  continue utility resumes the next iteration of the enclosed for, while, until, or select loop. If n is specified then resume at the n-
       th enclosed loop. If n is greater than the number of enclosing loops, the outermost enclosing loop shall be used.

       On this man page, ksh(1) commands that are preceded by one or two * (asterisks) are treated specially in the following ways:

       1.  Variable assignment lists preceding the command remain in effect when the command completes.

       2.  I/O redirections are processed after variable assignments.

       3.  Errors cause a script that contains them to abort.

       4.  Words that follow a command preceded by ** that are in the format of a variable assignment are expanded with the same rules as a  vari-
           able  assignment.  This means that tilde substitution is performed after the = sign, and also that word splitting and file name genera-
           tion are not performed.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE         |      ATTRIBUTE VALUE        |
       +-----------------------------+-----------------------------+
       |Availability                 |SUNWcsu                      |
       +-----------------------------+-----------------------------+

SEE ALSO

       csh(1), exit(1), ksh(1), sh( 1), attributes(5)

SunOS 5.10                                                          17 Jul 2002                                                           break(1)
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