Question

I have a program that logs into a server and issues commands. The results are printed out at the end of the script. The below code shows the script I have created to pass commands through ssh.

import pexpect

ssh_newkey = 'Are you sure you want to continue connecting'
# my ssh command line
p=pexpect.spawn('ssh user@00.00.00.00')

i=p.expect([ssh_newkey,'password:',pexpect.EOF])
if i==0:
    print "I say yes"
    p.sendline('yes')
    i=p.expect([ssh_newkey,'password:',pexpect.EOF])
if i==1:
    print "I have entered the password. I will now flip camera through ",
    p.sendline("user")
    i=p.expect('user@hol-NA:')
    p.sendline("cd /opt/ad/bin")
    i=p.expect('user@hol-NA:')
    p.sendline("./ptzflip")
    i=p.expect('user@hol-NA:')
elif i==2:
    print "I either got key or connection timeout"
    pass
results = p.before # print out the result

print results

The results that the program prints out is:

Value = 1800
Min = 0
Max = 3600
Step = 1

I want to capture the values that are printed out.

In reponse to the questions below. I want to capture eg. ‘Value’ as a variable and ‘1800’ as its value. I have tried to separate it in a dictionary as mentioned below but I get an error. When I enter:

results_dict = {} 
for line in results: 
    name, val = line.split(' = ') 
    results_dict[name] = val

I get an error:

Traceback (most recent call last):
  File "ptest.py", line 30, in <module>
    name, val = line.split(' = ') 
ValueError: need more than 1 value to unpack

When I check this code in Python it stores these values as a string. It stores it as:

'/opt/ad/bin$ ./ptzflip\r\nValue = 1800\r\nMin = 0\r\nMax = 3600\r\nStep = 1\r\n'

Can anyone help in this problem. Thanks

Answer 1

Are Value = 1800 etc. the contents of results? And you want to “capture” that?

Do you mean you want to parse those results? Or execute them as python?

If the former you could do something like (untested, unclean, doesn’t deal carefully with whitespace):

results_dict = {}
for line in results.splitlines():
    try:
        name, val = line.split(' = ')
    except ValueError:
        continue
    results_dict[name] = val

This gives you a python dictionary that you can use. If you know that the values are always numbers, you could convert them with int(val) or float(val)… (The try…except ignores lines of the incorrect form; there may be more robust ways to do this, such as if " = " in line)

If you actually want to end up with a variable named Value with the value 1800, you could use eval(results) [or a safer alternative], although this would need to remove lines without the right format first.