1 files changed, 29 insertions, 0 deletions
diff --git a/vish/builtin.py b/vish/builtin.py
new file mode 100644
index 0000000..ccfc5b3
--- /dev/null
+++ b/vish/builtin.py
@@ -0,0 +1,29 @@
+import os
+import sys
+
+class TooManyArguments(Exception):
+    pass
+
+
+def pwd(args: list, stdin=sys.stdin, stdout=sys.stdout):
+    if not len(args) == 0:
+        raise TooManyArguments()
+
+    print(os.getcwd(), file=stdout)
+
+
+def chdir(args: list, stdin=sys.stdin, stdout=sys.stdout):
+    if len(args) == 0:
+        os.chdir(os.getenv("HOME"))
+    elif len(args) == 1:
+        os.chdir(next(iter(args)))
+    else:
+        raise TooManyArguments()
+
+
+def export(args: list, stdin=sys.stdin, stdout=sys.stdout):
+    if len(args) == 0:
+        for key, value in sorted(os.environ.items()):
+            print(f"{key}={value}", file=stdout)
+    else:
+        raise NotImplementedError()