extraction of data from .dat file

Hi Guys, I've looked everywhere but I don't seem to find a solution:

I have .dat files, with neurophysiological recordings of my participants, which contain both text and numbers, as you can see from the example below. What I need to do is:

1) Create a variable "Header" that contains only the initial 25 rows

2) Create new .dat files (or variables) from the original file which contain only data according to the position of the trigger "4" (that you can see in the first column of the numeric part of the file).

The first new .dat file will contain the data (all columns) included between the 26th row and the first "4". The second file will contain the data between the first "4" and the second "4", the third between the second "4" and the third "4", and so on........until the last file/variable which will contain the data between the last "4" and the end of the file.

3) Re-insert the Header part (the 25 rows of mixed stuff) at the beginning of each new .dat file (or new variable), to create .dat files with the header + the extract of the data.

Thank you so much in advance!!!!

P.S. the number of triggers may vary between 18 and 21 but the Header lines are always 25.

[Start/Stop Time]

START=2017/02/13 21:07:28

STOP=2017/02/13 22:27:06

[Measurement Profile]

TITLE=Mat Mar

EVENT_MODE=Event-Related

EVENT_TYPE=MANU

EVENT_T0=0,EVT1

EVENT_T1=0,EVT4

EVENT_T2=0,EVT3

EVENT_REPEAT=

[User Profile]

NAME=Mat Mar

AGE=64

GENDER=Female

Dominant Hand=Right-Handed

[HEADER]

TRG_MODE=8002

LED_POWER=0000

AGC_GAIN=0020,0010,0030,0020,0030,0050

[CH_CONFIG]

1,7,2,8,9,14,15,21,16,22,23,28,29,35,30,36

[CAL(CAL1-L1,CAL1-L2,...,CAL36-L1,CAL36-L2)(0:good/3:unuse/1:over/2:under)]

10,10,10,10,03,03,03,03,03,03,03,03,10,10,10,10,10,10,03,03,03,03,03,03,03,03,10,10,10,10,10,10,03,03,03,03,03,03,03,03,10,10,10,10,10,10,

[DATA(EVENT,CH1-L1(840nm),CH1-L2(770nm),...,CH36-L1,CH36-L2);FAST]

0000,1614,938,2405,1633,16,10,15,10,10,7,10,3,605,293,646,388,1708,1042,10

0000,1599,932,2397,1630,15,9,13,11,10,7,10,3,599,291,641,387,1699,1038,10,8

0000,1591,929,2391,1629,16,9,14,9,11,6,8,3,593,289,637,385,1691,1036,10,8,9

0004,1591,928,2392,1626,16,9,14,10,10,6,9,4,592,288,636,384,1690,1036,9,8,9

0000,1594,930,2393,1627,16,10,13,9,10,7,7,3,594,290,636,383,1691,1037,10,8,9

0000,1614,938,2405,1633,16,10,15,10,10,7,10,3,605,293,646,388,1708,1042,10

0004,1599,932,2397,1630,15,9,13,11,10,7,10,3,599,291,641,387,1699,1038,10,8

0000,1591,929,2391,1629,16,9,14,9,11,6,8,3,593,289,637,385,1691,1036,10,8,9

0000,1591,928,2392,1626,16,9,14,10,10,6,9,4,592,288,636,384,1690,1036,9,8,9

0000,1594,930,2393,1627,16,10,13,9,10,7,7,3,594,290,636,383,1691,1037,10,8,9

0000,1614,938,2405,1633,16,10,15,10,10,7,10,3,605,293,646,388,1708,1042,10

0004,1599,932,2397,1630,15,9,13,11,10,7,10,3,599,291,641,387,1699,1038,10,8

0000,1591,929,2391,1629,16,9,14,9,11,6,8,3,593,289,637,385,1691,1036,10,8,9

0004,1591,928,2392,1626,16,9,14,10,10,6,9,4,592,288,636,384,1690,1036,9,8,9

0000,1594,930,2393,1627,16,10,13,9,10,7,7,3,594,290,636,383,1691,1037,10,8,9

0000,1614,938,2405,1633,16,10,15,10,10,7,10,3,605,293,646,388,1708,1042,10

..................................................................