main+command_manager: allow symlink shortcuts to subcommands

  # ln -s /bin/clufter /bin/ccs-disable-rg
  # ccs-disable-rg -h | head -n1
  > Usage: ccs-disable-rg [<cmd option ...>]

Signed-off-by: Jan Pokorný <jpokorny@redhat.com>

2 files changed, 14 insertions, 8 deletions

diff --git a/command_manager.py b/command_manager.py
index 318ac4f..3dac1b4 100644
--- a/command_manager.py
+++ b/command_manager.py
@@ -113,8 +113,9 @@ class CommandManager(PluginManager):
             if opts.help:
                 usage = ('\n' + len('Usage: ') * ' ').join(map(
                     lambda c:
-                        "%prog [<global option> ...] {0} [<cmd option ...>]"
-                        .format(c),
+                        "{0}{1} [<cmd option ...>]"
+                        .format("%prog [<global option> ...] "
+                                if parser.prog != c else '', c),
                     sorted(set([cmd, canonical_cmd]),
                            key=lambda i: int(i == canonical_cmd))
                 ))
diff --git a/main.py b/main.py
index b9d3c70..6d33a13 100644
--- a/main.py
+++ b/main.py
@@ -9,7 +9,7 @@ import logging
 from optparse import OptionParser, \
                      OptionGroup, \
                      IndentedHelpFormatter
-from os.path import basename
+from os.path import basename, realpath
 from platform import system, linux_distribution
 try:
     from platform import _supported_dists
@@ -24,7 +24,7 @@ from .completion import Completion
 from .error import EC
 from .facts import aliases_dist
 from .utils import args2sgpl, head_tail, identity
-from .utils_prog import ExpertOption, make_options, set_logging
+from .utils_prog import ExpertOption, make_options, set_logging, which
 
 
 _system = system().lower()
@@ -257,8 +257,10 @@ def run(argv=None, *args):
     # re option parser: only one instance is used, modified along
     ec = EC.EXIT_SUCCESS
     argv = list(argv) + list(args) if argv else list(args)
-    prog, args = (argv[0], argv[1:]) if argv else ('<script>', [])
+    prog, argv = (argv[0], argv[1:]) if argv else ('<script>', [])
     prog_simple = basename(prog)
+    prog_full = prog if prog != prog_simple else which(prog_simple, '.', '')
+    prog_real = basename(realpath(prog_full))
 
     parser = SharedOptionParser(prog=prog_simple, add_help_option=False)
     parser.disable_interspersed_args()  # enforce ordering as per "usage"
@@ -272,8 +274,8 @@ def run(argv=None, *args):
         option_list=make_options(opts_common)
     )
 
-    opts, args = parser.parse_args(args)
-    if opts.help is None:
+    opts, args = parser.parse_args(argv)
+    if prog_simple == prog_real and opts.help is None:
         # options that return/exit + don't need plugin resolutions (not help)
         if opts.version:
             loglevel = logging.getLevelName(opts.loglevel)
@@ -296,7 +298,8 @@ def run(argv=None, *args):
     cm = CommandManager.init_lookup(ext_plugins=not opts.skip_ext,
                                     ext_plugins_user=opts.ext_user,
                                     system=opts.sys, system_extra=opts.dist)
-    if not opts.help and (opts.list or opts.completion or not args):
+    if prog_simple == prog_real and not opts.help \
+       and (opts.list or opts.completion or not args):
         cmds = cm.pretty_cmds(ind=' ' * parser.formatter.indent_increment,
                               linesep_width=2,
                               cmds_intro="Commands"
@@ -322,6 +325,8 @@ def run(argv=None, *args):
                         " just precede or follow it with `--help'.")
             )
         return ec
+    elif prog_simple != prog_real:
+        args = [prog_simple] + argv
 
     # prepare option parser to be reused by sub-commands
     parser.enable_interspersed_args()