python執行shell-subprocess模組

python執行shell-subprocess模組
python執行shell-subprocess模組call

retcode = subprocess.call([“ls”, “-l”])
call我感覺相當與os.popen，只能執行命令，看傳回值。取不到命令輸出。所以還是得用Popen,注意P大寫。

Popen基本用法:

child1 = subprocess.Popen(["cat","/etc/passwd"],stdout=subprocess.PIPE)

或者:

child1 = subprocess.Popen("pwd",stdout=subprocess.PIPE)

然後用communicate()互動。值

res=child1.communicate()type(res)

res傳回值是一個tuple類型的值(不可變數組)。要取命令輸出只需取第一個參數在後面[0]即可:

res2=child1.communicate()[0]

communicate() returns a tuple (stdout, stderr).

如果多個命令，管道相連，就是這樣:

child1 = subprocess.Popen(["cat","/etc/passwd"], stdout=subprocess.PIPE)child2 = subprocess.Popen(["grep","0:0"],stdin=child1.stdout, stdout=subprocess.PIPE)out = child2.communicate()[0]print out