hopefully this is a quick an easy on! I am trying to do a search for a hostname on a device and then use that hostname to dictate the config that is sent to it via netmiko. I think I'm failing because the output is not on one line. As a test at the moment I am just trying to print the output as follows:

device_name = net_connect.send_command('show running-config sys global-settings hostname')
hostname = re.search('^hostname', device_name, re.M)
print(hostname)

When I run the above command on the device manually the output is like this:

sys global-settings {

    hostname triton.lakes.travp.net

}

So do I need to adjust the re.search to take into account the seperate lines to just capture the 'hostname triton.lakes.travp.net' line?

Many thanks

CodePudding user response：

re

(?=...)

Matches if ... matches next, but doesn’t consume any of the string. This is called a lookahead assertion. For example, Isaac (?=Asimov) will match 'Isaac ' only if it’s followed by 'Asimov'.

(?<=...)

Matches if the current position in the string is preceded by a match for ... that ends at the current position. This is called a positive lookbehind assertion. (?<=abc)def will find a match in 'abcdef', since the lookbehind will back up 3 characters and check if the contained pattern matches.

Demo: (?<={).*(?=})

It means to match strings beginning with { and ending with }

import re

s = """
sys global-settings {

    hostname triton.lakes.travp.net

}
"""

print(re.search(r"(?<={)\s (hostname . ?)\s (?=})", s).group(1))

# hostname triton.lakes.travp.net