+_p4_version_string = None
+def p4_version_string():
+ """Read the version string, showing just the last line, which
+ hopefully is the interesting version bit.
+
+ $ p4 -V
+ Perforce - The Fast Software Configuration Management System.
+ Copyright 1995-2011 Perforce Software. All rights reserved.
+ Rev. P4/NTX86/2011.1/393975 (2011/12/16).
+ """
+ global _p4_version_string
+ if not _p4_version_string:
+ a = p4_read_pipe_lines(["-V"])
+ _p4_version_string = a[-1].rstrip()
+ return _p4_version_string
+