For loops
1. Simple examples

1.1 Simple loop without needing to expand

  $ msh -c "for i in a b c; do echo hello; done"
  hello
  hello
  hello


1.2. Simple word list to echo

  $ msh -c "for foo in a b c; do echo \$foo; done"
  a
  b
  c

1.3 In conjunction with path globbing

  $ touch hello.txt world.txt
  $ sh -c "for foo in *.txt; do echo \$foo; done"
  hello.txt
  world.txt
  $ msh -c "for foo in *.txt; do echo \$foo; done"
  hello.txt
  world.txt

1.4 Subshells and stuff!

  $ cat >test.sh << EOF
  > echo hello > abc.md
  > echo world > def.md
  > for f in *.md; do
  >  rev "\$f" > "\$(basename -- "\$f" .md).rev"
  > done
  > EOF

  $ msh test.sh
  $ ls
  abc.md
  abc.rev
  def.md
  def.rev
  hello.txt
  test.sh
  world.txt

1.5 Pipelines

  $ cat >test.sh << EOF
  > for i in "olleh" "dlrow"; do
  >   echo \$i
  > done | rev
  > EOF

  $ sh test.sh
  hello
  world
  $ msh test.sh
  hello
  world

1.6 Redirects

  $ cat > test.sh << EOF
  > for i in a b; do
  >   echo \$i 
  > done > hello.txt
  > echo "The file contains:"
  > cat hello.txt
  > EOF

  $ sh test.sh
  The file contains:
  a
  b
  $ msh test.sh 
  The file contains:
  a
  b

1.7 Good handling of the for-loop context.

  $ cat > test.sh << EOF
  > VALUES="a b c d"
  > ok="false"
  > 
  > for v in \$VALUES; do
  >   if [ \$v = "c" ]; then ok="true"; fi
  > done
  > 
  > echo "ok is \$ok"
  > EOF

  $ sh test.sh
  ok is true
  $ msh test.sh
  ok is true

1.8 Handling of empty expansions

  $ cat > test.sh << EOF
  > SUITE="stable"
  > EXTRA_SUITES=""
  > for s in \$SUITE \$EXTRA_SUITES \$UNASSIGNED; do
  >   echo "Downloading /foo/\$s/bar"
  > done
  > EOF

  $ sh test.sh
  Downloading /foo/stable/bar
  $ msh test.sh
  Downloading /foo/stable/bar