From b05a5d4bf5dab402e1eb6547c98d839afb65bf1c Mon Sep 17 00:00:00 2001
From: Nathan Hoad <nathan@getoffmalawn.com>
Date: Sat, 22 Apr 2017 10:52:34 +1000
Subject: [PATCH] Implement an alias alias, matching what sh's alias does.

---
 news/alias-command.rst | 13 +++++++++++++
 xontrib/bashisms.py    | 30 ++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 news/alias-command.rst

diff --git a/news/alias-command.rst b/news/alias-command.rst
new file mode 100644
index 000000000..1e8d52264
--- /dev/null
+++ b/news/alias-command.rst
@@ -0,0 +1,13 @@
+**Added:**
+
+* Added an alias command, matching bash's implementation, available as part of bashisms.
+
+**Changed:** None
+
+**Deprecated:** None
+
+**Removed:** None
+
+**Fixed:** None
+
+**Security:** None
diff --git a/xontrib/bashisms.py b/xontrib/bashisms.py
index 74ad5d4cb..269bdbddb 100644
--- a/xontrib/bashisms.py
+++ b/xontrib/bashisms.py
@@ -1,7 +1,12 @@
 """Bash-like interface extensions for xonsh."""
+import shlex
+import sys
+
 from prompt_toolkit.keys import Keys
 from prompt_toolkit.filters import Condition, EmacsInsertMode, ViInsertMode
 
+__all__ = ()
+
 
 @events.on_transform_command
 def bash_preproc(cmd, **kw):
@@ -26,3 +31,28 @@ def custom_keybindings(bindings, **kw):
     def recall_last_arg(event):
         arg = __xonsh_history__[-1].cmd.split()[-1]
         event.current_buffer.insert_text(arg)
+
+
+def alias(args, stdin=None):
+    ret = 0
+
+    if args:
+        for arg in args:
+            if '=' in arg:
+                # shlex.split to remove quotes, e.g. "foo='echo hey'" into
+                # "foo=echo hey"
+                name, cmd = shlex.split(arg)[0].split('=', 1)
+                aliases[name] = shlex.split(cmd)
+            elif arg in aliases:
+                print('{}={}'.format(arg, aliases[arg]))
+            else:
+                print("alias: {}: not found".format(arg), file=sys.stderr)
+                ret = 1
+    else:
+        for alias, cmd in aliases.items():
+            print('{}={}'.format(alias, cmd))
+
+    return ret
+
+
+aliases['alias'] = alias