lines 2

import os

def line_trim(s):
    return s.split()[0]

dir = '/home/caveat/tmp/'
flist = os.listdir(dir)
for i in flist:
    fullname = os.path.join(dir,i)
    if os.path.isfile(fullname) and not i.endswith('.txt'):
        f = open(fullname,'r')
        np = fullname + '.txt'
        g = open(np,'w')
        for j in f.readlines():
            g.write(line_trim(j)+'\n')
        g.close()
        f.close()