Here is my code
f = os.popen("java -version")
for i in f.readlines():
print "result, ", i,
Basically I want the output of java -version to be stored in f. What happens is, after the first line of the script executes, the java -version information is printed out, but not stored in f, hence the third line of code is not executed at all. This code works for other commands such as "ls -la", but not for java -version. Any ideas as to why?
Thanks in advance.
Since java -version goes to stderr, not to stdin, you have to redirect it:
f = os.popen("java -version 2>&1")
for i in f.readlines():
print "result, ", i,
better yet, use the subprocess module, which is designed to make this kind of things easier:
print subprocess.check_output("java -version", stderr=subprocess.STDOUT, shell=True)
try something like:
from subprocess import Popen, PIPE
stdout,stderr= Popen(['java','-version'], shell=False, stderr=PIPE).communicate()
print(stderr)
output:
b'java version "1.6.0_20"\nOpenJDK Runtime Environment (IcedTea6 1.9.13) (6b20-1.9.13-0ubuntu1~10.10.1)\nOpenJDK Client VM (build 19.0-b09, mixed mode, sharing)\n'
stderr=PIPE, now it'll work.