printenv: Add printenv.py

Author: Expertcoderz

src/printenv.py

@@ -0,0 +1,37 @@
+#!/usr/bin/python3
+
+import os
+import sys
+from optparse import OptionParser
+
+
+def printenv(opts, var_names: list[str]):
+    endchar = "\0" if opts.null else "\n"
+
+    if not var_names:
+        for name, value in os.environ.items():
+            print(f"{name}={value}", end=endchar)
+        return
+
+    failed = False
+    for name in var_names:
+        if value := os.environ.get(name):
+            print(f"{name}={value}", end=endchar)
+        else:
+            failed = True
+
+    if failed:
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    parser = OptionParser(
+        usage="Usage: %prog [OPTION] [VARIABLE]...",
+        description="Print VARIABLE(s) or all environment variables, and their corresponding values.",
+        add_help_option=False,
+    )
+    parser.add_option("--help", action="help", help="show usage information and exit")
+
+    parser.add_option("-0", "--null", action="store_true")
+
+    printenv(*parser.parse_args())