ref: 6d25e194e2160a6ed8b2a7e399fff90e2215ff3c
dir: /sys/src/cmd/python/Demo/scripts/mkrcs.py/
#! /usr/bin/env 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 '%r is a symlink to %r' % (rcs, os.readlink(rcs))
return
if os.path.isdir(rcs):
print '%r is an ordinary directory' % (rcs,)
return
if os.path.exists(rcs):
print '%r is a file?!?!' % (rcs,)
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 =', repr(p)
while not os.path.isdir(os.path.join(p, rcstree)):
head, tail = os.path.split(p)
#print 'head = %r; tail = %r' % (head, tail)
if not tail:
print 'Sorry, no ancestor dir contains %r' % (rcstree,)
return
p = head
up = os.path.join(os.pardir, up)
down = os.path.join(tail, down)
#print 'p = %r; up = %r; down = %r' % (p, up, 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 '%r already exists' % (there, )
else:
print 'making %r' % (there,)
makedirs(there)
print 'making symlink %r -> %r' % (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)
if __name__ == "__main__":
main()