File splitter based on (multiple) keyword searches (must be at line start!). Keeps 1st line as header.

file_splitter_by_search.py

#!/usr/bin/python3
#-*- coding: utf-8 -*-

import re, sys
with open(sys.argv[1]) as inputf: 
    c = 1
    ls = inputf.readlines()
    fromline = 1

    for splitter in sys.argv[2:]:
        for cc,ll in enumerate(ls):
            #print('testing', splitter, ll)
            if re.match("^"+splitter, ll):
                toline=cc
                #print('found match on line', cc,ll)
                break
        else:
            print("splitting error - no match for", splitter)

        with open(sys.argv[1].replace('.txt', '') + ('_cycle%d.txt'%c), 'w') as outputf: 
            print('exporting', fromline,':',toline, 'c=',c)
            outputf.write(''.join(ls[0:1]+ls[fromline:toline]))
            c += 1

        fromline = toline

    with open(sys.argv[1].replace('.txt', '') + ('_cycle%d.txt'%c), 'w') as outputf: 
        print('exporting', fromline,':',len(ls), 'c=',c)
        outputf.write(''.join(ls[0:1]+ls[fromline:]))

Example: Contents of the "aa" file:

HEADER
adam 
barbora
cyril
dusan
ema
filip

Invocation:
python3 splitter.py aa dusa

Output in "aa_cycle1.txt"

HEADER
adam 
barbora
cyril

And in "aa_cycle2.txt"

HEADER
dusan
ema
filip

Note you can detect the rising edges in your (x,y) data using e.g. python:
convol = 2**-np.linspace(-2,2,5)**2; y = np.convolve(y,convol/np.sum(convol), mode='same') ## simple smoothing
skippy = (y[1:]-y[:-1])
skipx = (x[:-1])[skippy>((np.max(y)-np.min(y))/30)]
print((x[np.argsort(-skippy)])[:30])