---
 lshell/shellcmd.py |   77 ++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 71 insertions(+), 6 deletions(-)

--- a/lshell/shellcmd.py
+++ b/lshell/shellcmd.py
@@ -28,6 +28,7 @@ import readline
 import glob
 import subprocess
 
+from time import gmtime, strftime
 from utils import get_aliases
 
 
@@ -50,6 +51,9 @@ class ShellCmd(cmd.Cmd, object):
         else:
             self.stderr = stderr
 
+	# create a devnull device
+	self.devnull = open(os.devnull, 'w')
+
         self.args = args
         self.conf = userconf
         self.log = self.conf['logpath']
@@ -145,13 +149,63 @@ class ShellCmd(cmd.Cmd, object):
         self.g_cmd, self.g_arg, self.g_line = ['', '', ''] 
         return object.__getattribute__(self, attr)
 
+    def check_prompt(self, var, value):
+	""" check if user is attempting to
+	modify shell prompt and if so then
+	update the prompt
+	"""
+	if 'PS' in var:
+	    if 'PS1' in var:
+		# update prompt
+		self.promptbase = self.setprompt(
+				{'prompt' : value.strip('\n').strip('\r')})
+		self.updateprompt(os.getcwd())
+	    else:
+		self.log.critical("*** forbidden %s prompt change requested. "
+				  "Only PS1 changes permissible" % var)
+
+
     def setprompt(self, conf):
         """ set prompt used by the shell
         """
         if conf.has_key('prompt'):
             promptbase = conf['prompt']
-            promptbase = promptbase.replace('%u', getuser())
-            promptbase = promptbase.replace('%h', os.uname()[1].split('.')[0])
+	    # Recognize shell name control command
+	    promptbase = re.sub(r'\\s', 'lshell',
+				promptbase)
+	    # Recognize username control command
+	    promptbase = re.sub(r'\\u|%u', getuser(),
+				promptbase)
+	    # Recognize hostname control command
+	    promptbase = re.sub(r'\\h|%h', os.uname()[1].split('.')[0],
+				promptbase)
+	    # Recognize full hostname control command
+	    promptbase = re.sub(r'\\H', os.uname()[1],
+				promptbase)
+	    # Recognize time control commands
+	    promptbase = re.sub(r'\\t', strftime("%H:%M:%S", gmtime()),
+				promptbase)
+	    promptbase = re.sub(r'\\T', strftime("%I:%M:%S", gmtime()),
+				promptbase)
+	    promptbase = re.sub(r'\\A', strftime("%H:%M", gmtime()),
+				promptbase)
+	    promptbase = re.sub(r'\\@', strftime("%I:%M:%S%p", gmtime()),
+				promptbase)
+	    promptbase = re.sub(r'\\d', strftime("%a %b %d", gmtime()),
+				promptbase)
+	    ########################################################
+	    #  The following control commands are not supported:   #
+	    #  v  - the shell version 				   #
+	    #  V  - the shell release version			   #
+	    #  w  - Complete path of current working directory	   #
+	    #  W  - the basename of the current working directory  #
+	    #  !  - the history number of this command		   #
+	    #  #  - the command number of this command		   #
+	    #  $? - status of the last command		           #
+	    # $() - any command executions			   #
+	    ########################################################
+	    promptbase = re.sub(r'\\v|\\V|\\w|\\W|\\!|\\#|\\\$\?|\\\$\(.*\)|\\\$', '',
+				promptbase)
         else:
             promptbase = getuser()
 
@@ -199,7 +253,7 @@ class ShellCmd(cmd.Cmd, object):
     def export(self):
         """ export environment variables """
         # if command contains at least 1 space
-        if self.g_line.count(' '):
+	if self.g_line.count(' '):
             env = self.g_line.split(" ", 1)[1]
             # if it conatins the equal sign, consider only the first one
             if env.count('='):
@@ -216,6 +270,10 @@ class ShellCmd(cmd.Cmd, object):
                     cin, cout = os.popen2('`which echo` %s' % value)
                 value = cout.readlines()[0]
 
+		# check if new exported environment
+		# is a prompt change command
+		self.check_prompt(var, value)
+
                 os.environ.update({var: value.rstrip()})
 
     def source(self):
@@ -485,11 +543,14 @@ class ShellCmd(cmd.Cmd, object):
                     p = subprocess.Popen( "`which echo` %s" % item,
                                           shell=True,
                                           stdin=subprocess.PIPE,
-                                          stdout=subprocess.PIPE )
+                                          stdout=subprocess.PIPE,
+					  stderr = self.devnull )
                     (cin, cout) = (p.stdin, p.stdout)
                 except ImportError:
-                    cin, cout = os.popen2('`which echo` %s' % item)
-                item = cout.readlines()[0].split(' ')[0].strip()
+                    cin, cout = os.popen2('`which echo` %s 2>/dev/null' % item)
+               	shellresponse = cout.readlines()
+                if shellresponse:
+		    item = shellresponse[0].split(' ')[0].strip()
                 item = os.path.expandvars(item)
             tomatch = os.path.realpath(item)
             if os.path.isdir(tomatch) and tomatch[-1] != '/': tomatch += '/'
@@ -559,6 +620,10 @@ class ShellCmd(cmd.Cmd, object):
 	    if len(env) is not 2:
 		continue
             newenv.update(dict([env]))
+	    # check if the new environment includes
+	    # any Shell prompt change commands
+	    self.check_prompt(env[0], env[1])
+
 	os.environ.update(newenv)
 
     def loginCmdParse(self, script):