1 files changed, 46 insertions, 0 deletions
diff --git a/waflib/extras/print_commands.py b/waflib/extras/print_commands.py
new file mode 100644
index 00000000..3005c3ee
--- /dev/null
+++ b/waflib/extras/print_commands.py
@@ -0,0 +1,46 @@
+#! /usr/bin/env python
+
+"""
+Illustrate how to override a class method to do something
+
+In this case, print the commands being executed as strings
+(the commands are usually lists, so this can be misleading)
+"""
+
+import sys
+from waflib import Context, Utils, Logs
+
+def exec_command(self, cmd, **kw):
+	subprocess = Utils.subprocess
+	kw['shell'] = isinstance(cmd, str)
+
+	txt = cmd
+	if isinstance(cmd, list):
+		txt = ' '.join(cmd)
+
+	print(txt)
+	Logs.debug('runner_env: kw=%s' % kw)
+
+	try:
+		if self.logger:
+			# warning: may deadlock with a lot of output (subprocess limitation)
+
+			self.logger.info(cmd)
+
+			kw['stdout'] = kw['stderr'] = subprocess.PIPE
+			p = subprocess.Popen(cmd, **kw)
+			(out, err) = p.communicate()
+			if out:
+				self.logger.debug('out: %s' % out.decode(sys.stdout.encoding or 'iso8859-1'))
+			if err:
+				self.logger.error('err: %s' % err.decode(sys.stdout.encoding or 'iso8859-1'))
+			return p.returncode
+		else:
+			p = subprocess.Popen(cmd, **kw)
+			return p.wait()
+	except OSError:
+		return -1
+
+Context.Context.exec_command = exec_command
+
+