diff --git a/utils/lit/ShCommands.py b/utils/lit/ShCommands.py
new file mode 100644
index 0000000..be3e680
--- /dev/null
+++ b/utils/lit/ShCommands.py
@@ -0,0 +1,86 @@
+import ShUtil
+
+class Command:
+    def __init__(self, args, redirects):
+        self.args = list(args)
+        self.redirects = list(redirects)
+
+    def __repr__(self):
+        return 'Command(%r, %r)' % (self.args, self.redirects)
+
+    def __cmp__(self, other):
+        if not isinstance(other, Command):
+            return -1
+
+        return cmp((self.args, self.redirects),
+                   (other.args, other.redirects))
+
+    def toShell(self, file):
+        for arg in self.args:
+            if "'" not in arg:
+                quoted = "'%s'" % arg
+            elif '"' not in arg and '$' not in arg:
+                quoted = '"%s"' % arg
+            else:
+                raise NotImplementedError,'Unable to quote %r' % arg
+            print >>file, quoted,
+
+            # For debugging / validation.
+            dequoted = list(ShUtil.ShLexer(quoted).lex())
+            if dequoted != [arg]:
+                raise NotImplementedError,'Unable to quote %r' % arg
+
+        for r in self.redirects:
+            if len(r[0]) == 1:
+                print >>file, "%s '%s'" % (r[0][0], r[1]),
+            else:
+                print >>file, "%s%s '%s'" % (r[0][1], r[0][0], r[1]),
+
+class Pipeline:
+    def __init__(self, commands, negate=False, pipe_err=False):
+        self.commands = commands
+        self.negate = negate
+        self.pipe_err = pipe_err
+
+    def __repr__(self):
+        return 'Pipeline(%r, %r, %r)' % (self.commands, self.negate,
+                                         self.pipe_err)
+
+    def __cmp__(self, other):
+        if not isinstance(other, Pipeline):
+            return -1
+
+        return cmp((self.commands, self.negate, self.pipe_err),
+                   (other.commands, other.negate, self.pipe_err))
+
+    def toShell(self, file, pipefail=False):
+        if pipefail != self.pipe_err:
+            raise ValueError,'Inconsistent "pipefail" attribute!'
+        if self.negate:
+            print >>file, '!',
+        for cmd in self.commands:
+            cmd.toShell(file)
+            if cmd is not self.commands[-1]:
+                print >>file, '|\n ',
+
+class Seq:
+    def __init__(self, lhs, op, rhs):
+        assert op in (';', '&', '||', '&&')
+        self.op = op
+        self.lhs = lhs
+        self.rhs = rhs
+
+    def __repr__(self):
+        return 'Seq(%r, %r, %r)' % (self.lhs, self.op, self.rhs)
+
+    def __cmp__(self, other):
+        if not isinstance(other, Seq):
+            return -1
+
+        return cmp((self.lhs, self.op, self.rhs),
+                   (other.lhs, other.op, other.rhs))
+
+    def toShell(self, file, pipefail=False):
+        self.lhs.toShell(file, pipefail)
+        print >>file, ' %s\n' % self.op
+        self.rhs.toShell(file, pipefail)