how to perform
echo xyz | ssh [host]
(send xyz to host)
with python?
I have tried pexpect
pexpect.spawn('echo xyz | ssh [host]')
but it's performing
echo 'xyz | ssh [host]'
maybe other package will be better?
http://pexpect.sourceforge.net/pexpect.html#spawn
Gives an example of running a command with a pipe :
shell_cmd = 'ls -l | grep LOG > log_list.txt'
child = pexpect.spawn('/bin/bash', ['-c', shell_cmd])
child.expect(pexpect.EOF)
Previous incorrect attempt deleted to make sure no-one is confused by it.
You don't need pexpect to simulate a simple shell pipeline. The simplest way to emulate the pipeline is the os.system function:
os.system("echo xyz | ssh [host]")
A more Pythonic approach is to use the subprocess module:
p = subprocess.Popen(["ssh", "host"],
stdin=subprocess.PIPE, stdout=subprocess.PIPE)
p.stdin.write("xyz\n")
output = p.communicate()[0]
Related
I have tried to use subprocess.check_output() for getting the ps aux command using python but it looks like not working with the large grep string.
Can anyone have any solution?
subprocess.check_output('ps aux | grep "bin/scrapy" | grep "option1" | grep "option2" | grep "option3" | grep "option4" | grep "option5"' , shell =True)
You can use the following code snippet for executing commands on remote host
# create ssh client
ssh = paramiko.SSHClient()
# add host key
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
# connect to host
ssh.connect(hostname='somehost', username='someuser', password='somepass')
# Login using RSA key
# ssh.connect(hostname='somehost', username='someuser', key_filename='/home/someuser/.ssh/id_rsa')
# execute command
stdin, stdout, stderr = ssh.exec_command('ps aux')
# print output
for line in stdout:
print(line)
# close connection
ssh.close()
# Output
# $ python3 test.py
Yes, I have found the solution to achieve the output, We can use the following code snippet to find the PID as output.
Instead of using ps aux we can use psutil python library.
import psutil
args_list = ["option1", "option2", "option3"]
for process in psutil.process_iter():
try:
process_args_list = process.cmdline()
except psutil._exceptions.NoSuchProcess as err:
logger.info(f"Found error in psutil, Error: {err}")
continue
if all(item in process_args_list for item in args_list):
print(process.pid)
I am trying to assign to a variable the fingerprint of a pgp key in a bash subprocess of a python script.
Here's a snippet:
import subprocess
subprocess.run(
'''
export KEYFINGERPRINT="$(gpg --with-colons --fingerprint --list-secret-keys | sed -n 's/^fpr:::::::::\([[:alnum:]]\+\):/\1/p')"
echo "KEY FINGERPRINT IS: ${KEYFINGERPRINT}"
''',
shell=True, check=True,
executable='/bin/bash')
The code runs but echo shows an empty variable:
KEY FINGERPRINT IS:
and if I try to use that variable for other commands I get the following error:
gpg: key "" not found: Not found
HOWEVER, if I run the same exact two lines of bash code in a bash script, everything works perfectly, and the variable is correctly assigned.
What is my python script missing?
Thank you all in advance.
The problem is the backslashes in your sed command. When you paste those into a Python string, python is escaping the backslashes. To fix this, simply add an r in front of your string to make it a raw string:
import subprocess
subprocess.run(
r'''
export KEYFINGERPRINT="$(gpg --with-colons --fingerprint --list-secret-keys | sed -n 's/^fpr:::::::::\([[:alnum:]]\+\):/\1/p')"
echo "KEY FINGERPRINT IS: ${KEYFINGERPRINT}"
''',
shell=True, check=True,
executable='/bin/bash')
in order to run 2 commands in subprocess you need to run them one after each other or use ;
import subprocess
ret = subprocess.run('export KEYFINGERPRINT="$(gpg --with-colons --fingerprint --list-secret-keys | sed -n 's/^fpr:::::::::\([[:alnum:]]\+\):/\1/p')"; echo "KEY FINGERPRINT IS: ${KEYFINGERPRINT}"', capture_output=True, shell=True)
print(ret.stdout.decode())
you can use popen:
commands = '''
export KEYFINGERPRINT="$(gpg --with-colons --fingerprint --list-secret-keys | sed -n 's/^fpr:::::::::\([[:alnum:]]\+\):/\1/p')"
echo "KEY FINGERPRINT IS: ${KEYFINGERPRINT}"
'''
process = subprocess.Popen('/bin/bash', stdin=subprocess.PIPE, stdout=subprocess.PIPE)
out, err = process.communicate(commands)
print out
I am trying to store the output of a cmd command as a variable in python.
To achieve this i am using os.system() but os.system() just runs the process,it doesn't capture the output.
import os
PlatformName = os.system("adb shell getprop | grep -e 'bt.name'")
DeviceName = os.system("adb shell getprop | grep -e '.product.brand'")
DeviceID = os.system("adb shell getprop | grep -e 'serialno'")
Version = os.system("adb shell getprop | grep -e 'version.release'")
print(PlatformName)
print(DeviceName)
print(DeviceID)
print(Version)
Then i tried to use the subprocess module.
import subprocess
import os
PlatformName = subprocess.check_output(["adb shell getprop | grep -e 'bt.name'"])
DeviceName = subprocess.check_output(["adb shell getprop | grep -e '.product.brand'"])
DeviceID = subprocess.check_output(["adb shell getprop | grep -e 'serialno'"])
Version = subprocess.check_output(["adb shell getprop | grep -e 'version.release'"])
print(PlatformName)
print(DeviceName)
print(DeviceID)
print(Version)
I am getting the following error
FileNotFoundError: [WinError 2] The system cannot find the file
specified
How can I store the output of the command as a variable?
The issues here:
passing arguments like this (string in a list, with spaces) is really not recommended
passing arguments like this need shell=True for it to have a slight chance to work, and shell=True is known for security issues (and other issues as well, like non-portability)
grep is not standard on windows, and the pattern is a regex which means you'd probably have to escape . ("bt\.name").
when not found grep returns 1 and would make check_output fail.
when found grep returns match(es), and a newline, that you'd have to strip
I'd rewrite this:
PlatformName = subprocess.check_output(["adb shell getprop | grep -e 'bt.name'"])
as:
output = subprocess.check_output(["adb","shell","getprop"])
platform_name = next((line for line in output.decode().splitlines() if "bt.name" in line),"")
The second line is a "native" version of grep (without regexes). It returns the first occurrence of "bt.line" in the output lines or empty string if not found.
You don't need grep here (the above is not strictly equivalent, as it yields the first occurrence, not all the occurrences but that should be okay on your case). And your clients may not have grep installed on Windows.
Hey I got the same problem as you. Sub-process can do what you want even with the shell=False. The trick is the communicate() method.
with subprocess.Popen(cmdCode,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
cwd = workingDir,
bufsize=1,
universal_newlines = True) as proc:
#output is stored in proc.stdout
#errors are stored in proc.stderr
Now you just need a little function to scan the proc.stdout for the information you need: PlatformName, etc
I am trying to automate the process of executing a command. When I this command:
ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10
Into a termianl I get the response:
%CPU PID USER COMMAND
5.7 25378 stackusr whttp
4.8 25656 stackusr tcpproxy
But when I execute this section of code I get an error regarding the format specifier:
if __name__ == '__main__':
fullcmd = ['ps','-eo','pcpu,pid,user,args | sort -k 1 -r | head -10']
print fullcmd
sshcmd = subprocess.Popen(fullcmd,
shell= False,
stdout= subprocess.PIPE,
stderr= subprocess.STDOUT)
out = sshcmd.communicate()[0].split('\n')
#print 'here'
for lin in out:
print lin
This is the error showen:
ERROR: Unknown user-defined format specifier "|".
********* simple selection ********* ********* selection by list *********
-A all processes -C by command name
-N negate selection -G by real group ID (supports names)
-a all w/ tty except session leaders -U by real user ID (supports names)
-d all except session leaders -g by session OR by effective group name
-e all processes -p by process ID
T all processes on this terminal -s processes in the sessions given
a all w/ tty, including other users -t by tty
g OBSOLETE -- DO NOT USE -u by effective user ID (supports names)
r only running processes U processes for specified users
x processes w/o controlling ttys t by tty
I have tryed placing a \ before the | but this has not effect.
You would need to use shell=True to use the pipe character, if you are going to go down that route then using check_output would be the simplest approach to get the output:
from subprocess import check_output
out = check_output("ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10",shell=True,stderr=STDOUT)
You can also simulate a pipe with Popen and shell=False, something like:
from subprocess import Popen, PIPE, STDOUT
sshcmd = Popen(['ps', '-eo', "pcpu,pid,user,args"],
stdout=PIPE,
stderr=STDOUT)
p2 = Popen(["sort", "-k", "1", "-r"], stdin=sshcmd.stdout, stdout=PIPE)
sshcmd.stdout.close()
p3 = Popen(["head", "-10"], stdin=p2.stdout, stdout=PIPE,stderr=STDOUT)
p2.stdout.close()
out, err = p3.communicate()
How do I place output of bash command to Python variable?
I am writing a Python script, which I want to enter the output of
bash command:
rpm -qa --qf '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n' | grep -v 'Red Hat'|wc -l, and place it to Python variable, let say R.
After that I want to do, Python if R != 0
then run some Linux command.
How do I achieve that?
There are various options, but the easiest is probably using subprocess.check_output() with shell=True although this can be security hazard if you don't fully control what command is passed in.
import subprocess
var = subprocess.check_output('rpm -qa --qf '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n' | grep -v 'Red Hat'|wc -l', shell = True)
var = int(var)
You need to use shell=True as otherwise the pipes would not be interpreted.
If you need more control you might want to look at plumbum where you can do:
from plumbum.cmd import rpm, grep, wc
chain = rpm["-qa", "--qf", r"%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n"] | grep["-v", "Red Hat"] | wc["-l"]
R = int(chain())
Although I would probably not invoke wc and get the whole output and count its length within python (easier to check that you got just the lines that you expected, piping through wc -l throws away all of the details)
I would recommend envoy primarily because the API is much more intuitive to use for 90% of the use cases.
r = envoy.run('ls ', data='data to pipe in', timeout=2)
print r.status_code # returns status code
print r.std_out # returns the output.
See the Envoy Github page for more details.
You can use stdin.
#!/usr/bin/python
import sys
s = sys.stdin.read()
print s
Then you will run a bash command like this
echo "Hello" | ./myscript.py
Output
Hello
You can replace shell pipeline using Popen:
from subprocess import PIPE,Popen
p1 = Popen(["rpm", "-qa", "--qf", '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n'],stdout=PIPE)
p2 = Popen(["grep", "-v", 'Red Hat'],stdin=p1.stdout,stdout=PIPE)
p1.stdout.close()
p3 = Popen(["wc", "-l"],stdin=p2.stdout,stdout=PIPE)
p2.stdout.close()
out,err = p3.communicate()
If you just want to check if grep returned any matches then forget the wc - l and just check what grep returns:
p1 = Popen(["rpm", "-qa", "--qf", '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n'],stdout=PIPE)
p2 = Popen(["grep", "-v", 'Red Hat'],stdin=p1.stdout,stdout=PIPE)
p1.stdout.close()
out,err = p2.communicate()
if out:
...
Or just use check_output to run the rpm command and check the string for "Red Hat":
out = check_output(["rpm", "-qa", "--qf", '%{NAME}-%{VERSION}-%{RELEASE}.%{ARCH} %{VENDOR}\n'])
if "Red Hat" not in out:
....
Which is the same as inverting the search with grep -v then checking if there are any matches with wc.