While clauses.

  $ cat > test.sh << EOF
  > i=1
  > 
  > while [ "\$i" -le 5 ]
  > do
  >   echo "Iteration \$i..."
  >   i=\$((i + 1))
  > done
  > 
  > EOF

  $ sh test.sh
  Iteration 1...
  Iteration 2...
  Iteration 3...
  Iteration 4...
  Iteration 5...
  $ msh test.sh
  Iteration 1...
  Iteration 2...
  Iteration 3...
  Iteration 4...
  Iteration 5...

Also until loops.

  $ cat > test.sh << EOF
  > i=1
  > 
  > until [ "\$i" -ge 5 ]
  > do
  >   echo "Iteration \$i..."
  >   i=\$((i + 1))
  > done
  > 
  > EOF


  $ sh test.sh
  Iteration 1...
  Iteration 2...
  Iteration 3...
  Iteration 4...
  $ msh test.sh
  Iteration 1...
  Iteration 2...
  Iteration 3...
  Iteration 4...