A script which lists all buffers in all running vim instances

bls.py

#!/usr/bin/python
"""
The %prog (vim buffer ls) lists files hosted on all running vim servers. Star
before file indicates that the buffer is loaded.
"""

"""
Author: Marcin Szamotulski
"""

"""
Copyright Statement:
     bls is free software: you can redistribute it and/or modify it under the
     terms of the GNU General Public License as published by the Free Software
     Foundation, either version 3 of the License, or (at your option) any
     later version.

     bls is distributed in the hope that it will be useful, but WITHOUT ANY
     WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
     FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
     details.

     You should have received a copy of the GNU General Public License along
     with bls.  If not, see <http://www.gnu.org/licenses/>.
 """

import subprocess, re, sys, signal
from optparse import OptionParser
usage = "%prog"

parser  = OptionParser(usage=usage, description=__doc__, epilog="Author: Marcin Szamotulski, 2011")
(options, args) = parser.parse_args()

class TimeoutException(Exception):
    pass

servers=subprocess.Popen(['gvim', '--serverlist'], stdout=subprocess.PIPE ).communicate()[0].decode()
server_ls=list(filter(lambda s: s != "", servers.split("\n")))

def print_server(server):
    def timeout_handler(signum, frame):
        raise TimeoutException()

    signal.signal(signal.SIGALRM, timeout_handler)
    signal.alarm(1) # send a SIGALRM after 1 second,
                    # this function is only available on Unix,
                    # signal.alarm() works only with seconds.

    try:
        print("*** "+server+" ***")
        cmd=['vim', '--servername', server, '--remote-expr \"vim#ls()\"']
        subprocess.call(['vim', '--servername', server, '--remote-expr', 'vim#ls()'])
    except TimeoutException:
        print("--- "+server+" --- is not responding")

if len(server_ls) == 0:
    print("no vim/gvim instance is running")
    sys.exit(0)
for server in server_ls:
    if server != '':
        print_server(server)