title: zsh while loop exiting prematurely in a triple nested loop using floating point arithmetic
body: <p>I have a zsh script that should generate a bunch of Z-matrix files, but it exits the while loops after one iteration. N and M never increase </p>
  
  <pre><code>#!/bin/zsh
  n=0.5 
  m=0.5
  a=60.0
  i=1
  
  while [[ $n -le 1.5 ]];do
      while [[ $m -le 1.5 ]];do
          while [[ $a -le 160 ]];do
              echo $i
              echo "o" &gt; H2O.$i.Z
              eval echo "h  1" $n &gt;&gt; H2O.$i.Z
              eval echo "h  1" $m "2" $a &gt;&gt; H2O.$i.Z
  
              let i=$i+1
              let a=$a+5.0
          done
          let m=$m+0.05
      done
      let n=$n+0.05
  done
  </code></pre>
  
  <p>I'm new to zsh; is my syntax wrong?</p>