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>11.2. Nested Loops</H1
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>A <I
CLASS="FIRSTTERM"
>nested loop</I
> is a loop within a
	  loop, an inner loop within the body of an outer one. How
	  this works is that the first pass of the outer loop triggers
	  the inner loop, which executes to completion. Then the
	  second pass of the outer loop triggers the inner loop
	  again. This repeats until the outer loop finishes. Of course,
	  a <I
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	  loop would interrupt this process.</P
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>   1&nbsp;#!/bin/bash
   2&nbsp;# nested-loop.sh: Nested "for" loops.
   3&nbsp;
   4&nbsp;outer=1             # Set outer loop counter.
   5&nbsp;
   6&nbsp;# Beginning of outer loop.
   7&nbsp;for a in 1 2 3 4 5
   8&nbsp;do
   9&nbsp;  echo "Pass $outer in outer loop."
  10&nbsp;  echo "---------------------"
  11&nbsp;  inner=1           # Reset inner loop counter.
  12&nbsp;
  13&nbsp;  # ===============================================
  14&nbsp;  # Beginning of inner loop.
  15&nbsp;  for b in 1 2 3 4 5
  16&nbsp;  do
  17&nbsp;    echo "Pass $inner in inner loop."
  18&nbsp;    let "inner+=1"  # Increment inner loop counter.
  19&nbsp;  done
  20&nbsp;  # End of inner loop.
  21&nbsp;  # ===============================================
  22&nbsp;
  23&nbsp;  let "outer+=1"    # Increment outer loop counter. 
  24&nbsp;  echo              # Space between output blocks in pass of outer loop.
  25&nbsp;done               
  26&nbsp;# End of outer loop.
  27&nbsp;
  28&nbsp;exit 0</PRE
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>See <A
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>Example 27-11</A
> for an illustration of nested
	  <A
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>while loops</A
>, and <A
HREF="arrays.html#EX68"
>Example 27-13</A
> to see a while loop nested inside an <A
HREF="loops.html#UNTILLOOPREF"
>until loop</A
>.</P
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