Add --term-title-format flag to customize terminal title format

docs/source/whatsnew/pr/term-title-format-feature.rst

@@ -0,0 +1,2 b''
+An additional flag `--term-title-format` is introduced to allow the user to control the format of the terminal
+title.  It is specified as a python format string, and currently the only variable it will format is `{cwd}`.

IPython/core/magics/osm.py

@@ -352,7 +352,7 b' class OSMagics(Magics):'
             try:
                 os.chdir(os.path.expanduser(ps))
                 if hasattr(self.shell, 'term_title') and self.shell.term_title:
-                    set_term_title('IPython: ' + abbrev_cwd())
+                    set_term_title(self.shell.term_title_format.format(cwd=abbrev_cwd()))
             except OSError:
                 print(sys.exc_info()[1])
             else:
@@ -365,7 +365,7 b' class OSMagics(Magics):'
         else:
             os.chdir(self.shell.home_dir)
             if hasattr(self.shell, 'term_title') and self.shell.term_title:
-                set_term_title('IPython: ' + '~')
+                set_term_title(self.shell.term_title_format.format(cwd="~"))
             cwd = os.getcwd()
             dhist = self.shell.user_ns['_dh']
 

IPython/terminal/interactiveshell.py

@@ -179,6 +179,11 b' class TerminalInteractiveShell(InteractiveShell):'
         help="Automatically set the terminal title"
     ).tag(config=True)
 
+    term_title_format = Unicode("IPython: {cwd}",
+        help="Customize the terminal title format.  This is a python format string. " +
+             "Available substitutions are: {cwd}."
+    ).tag(config=True)
+
     display_completions = Enum(('column', 'multicolumn','readlinelike'),
         help= ( "Options for displaying tab completions, 'column', 'multicolumn', and "
                 "'readlinelike'. These options are for `prompt_toolkit`, see "
@@ -206,7 +211,7 b' class TerminalInteractiveShell(InteractiveShell):'
         # Enable or disable the terminal title.
         if self.term_title:
             toggle_set_term_title(True)
-            set_term_title('IPython: ' + abbrev_cwd())
+            set_term_title(self.term_title_format.format(cwd=abbrev_cwd()))
         else:
             toggle_set_term_title(False)