Initial revision

Demo/scripts/mkrcs.py

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+#! /ufs/guido/bin/sgi/python
+#! /usr/local/python
+
+# A rather specialized script to make sure that a symbolic link named
+# RCS exists pointing to a real RCS directory in a parallel tree
+# referenced as RCStree in an ancestor directory.
+# (I use this because I like my RCS files to reside on a physically
+# different machine).
+
+import os
+
+def main():
+	rcstree = 'RCStree'
+	rcs = 'RCS'
+	if os.path.islink(rcs):
+		print `rcs`, 'is a symlink to', `os.readlink(rcs)`
+		return
+	if os.path.isdir(rcs):
+		print `rcs`, 'is an ordinary directory'
+		return
+	if os.path.exists(rcs):
+		print `rcs`, 'is a file?!?!'
+		return
+	#
+	p = os.getcwd()
+	up = ''
+	down = ''
+	# Invariants:
+	# (1) join(p, down) is the current directory
+	# (2) up is the same directory as p
+	# Ergo:
+	# (3) join(up, down) is the current directory
+	#print 'p =', `p`
+	while not os.path.isdir(os.path.join(p, rcstree)):
+		head, tail = os.path.split(p)
+		#print 'head =', `head`, '; tail =', `tail`
+		if not tail:
+			print 'Sorry, no ancestor dir contains', `rcstree`
+			return
+		p = head
+		up = os.path.join(os.pardir, up)
+		down = os.path.join(tail, down)
+		#print 'p =', `p`, '; up =', `up`, '; down =', `down`
+	there = os.path.join(up, rcstree)
+	there = os.path.join(there, down)
+	there = os.path.join(there, rcs)
+	if os.path.isdir(there):
+		print `there`, 'already exists'
+	else:
+		print 'making', `there`
+		makedirs(there)
+	print 'making symlink', `rcs`, '->', `there`
+	os.symlink(there, rcs)
+
+def makedirs(p):
+	if not os.path.isdir(p):
+		head, tail = os.path.split(p)
+		makedirs(head)
+		os.mkdir(p, 0777)
+
+main()