I have an input file test.txt as:
host:dc2000
host:192.168.178.2
I want to get all of addresses of those machines by using:
grep "host:" /root/test.txt
And so on, I get command ouput via python:
import subprocess
file_input='/root/test.txt'
hosts=subprocess.Popen(['grep','"host:"',file_input], stdout= subprocess.PIPE)
print hosts.stdout.read()
But the result is empty string.
I don't know what problem I got. Can you suggest me how to solve?
Try that :
import subprocess
hosts = subprocess.check_output("grep 'host:' /root/test.txt", shell=True)
print hosts
check_output throws subprocess.CalledProcessError exception if grep finds no occurrence of the string in the file?Your code should work, are you sure that the user has the access right to read the file?
Also, are you certain there is a "host:" in the file? You might mean this instead:
hosts_process = subprocess.Popen(['grep','host:',file_input], stdout= subprocess.PIPE)
hosts_out, hosts_err = hosts_process.communicate()
Another solution, try Plumbum package(https://plumbum.readthedocs.io/):
from plumbum.cmd import grep
print(grep("host:", "/root/test.txt"))
print(grep("-n", "host:", "/root/test.txt")) #'-n' option
