擅长:python、mysql、java
<p>使用python的<code>with</code>语句:</p>
<pre><code>from sys import argv
import os
class MyPath(object):
def __init__(self, newpath):
self.newpath = newpath
def __enter__(self):
self.path = os.environ['PATH']
os.environ['PATH'] = self.newpath
return self.newpath
def __exit__(self, type, value, traceback):
os.environ['PATH'] = self.path
if __name__ == "__main__":
if len(argv) < 2:
print "usage: %s path" % (argv[0],)
exit(1)
print os.environ['PATH']
with MyPath(argv[1]) as newpath:
print newpath
print os.environ['PATH']
print os.environ['PATH']
</code></pre>
<p><code>python path.py whatever</code></p>
<p>产生:</p>
<p><code>/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
whatever
whatever
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games</code></p>