[spp] [PATCH 1/6] cli: add env command

[yasufum.o@gmail.com]

From: Yasufumi Ogawa <yasufum.o@gmail.com>

Add `env` command for displaying environmental variables. It displays
env variables starts with given keyword, or all variables if it is not
given. It is mainly used for finding variables related to SPP.

  # show variables starts with `SPP`
  spp > env SPP
  SPP_CTL_IP: 127.0.0.1
  SPP_FILE_PREFIX: spp

Signed-off-by: Yasufumi Ogawa <yasufum.o@gmail.com>
---
 src/cli/commands/help_msg.py | 10 ++++++++++
 src/cli/shell.py             | 11 +++++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/cli/commands/help_msg.py b/src/cli/commands/help_msg.py
index f303547..4cf2a1f 100644
--- a/src/cli/commands/help_msg.py
+++ b/src/cli/commands/help_msg.py
@@ -8,6 +8,16 @@ cmds = {
         spp > status
         """,
 
+        'env':
+        """Show environmental variables.
+
+        # show all env varibles.
+        spp > env
+
+        # show env varibles starts with `SPP`.
+        spp > env SPP
+        """,
+
         'record':
         """Save commands as a recipe file.
 
diff --git a/src/cli/shell.py b/src/cli/shell.py
index 0de6176..cfc343c 100644
--- a/src/cli/shell.py
+++ b/src/cli/shell.py
@@ -317,6 +317,17 @@ class Shell(cmd.Cmd, object):
         """Print help message of status command."""
         print(help_msg.cmds['status'])
 
+    def do_env(self, key):
+        """Display environmental variables."""
+
+        for k, v in sorted(os.environ.items()):
+            if k.startswith(key):
+                print("{}: {}".format(k, v))
+
+    def help_env(self):
+        """Print help message of env command."""
+        print(help_msg.cmds['env'])
+
     def do_pri(self, command):
         """Send a command to primary process."""
 
-- 
2.17.1