Shell Programming and Scripting

Hi, I need to change the 3rd field value based on the 4th field value using a shell script.
here are the fields;
05:15-23:59; 05:15-21:00; 11:00-18:00; TGSI; TGSummaryInfo_C ; ENTER VALID GAC
05:15-23:59; 05:15-21:00; 11:00-18:00; TGSI; TGSummaryInfo_E ; ENTER VALID GAC
05:15-23:59; 05:15-21:00; 11:00-18:00; TGSI; TGSummaryInfo_W ; ENTER VALID GAC

If 4th field is TGSummaryInfo_C (last character is "C"), i need to change the 3rd filed value from TGSI to TGSI_C; if 4th field is TGSummaryInfo_E
then i need to change 3rd filed value from TGSI to TGSI_E and so on.

Requesting help.

Regards,
Sam

Try this

Code:

awk '{split($5,arr,"_");sub(";","_"arr[2]";",$4);print}' file

Thanks Ahamed. Sorry for late reply. Was out of town.
Will try out and tell the result ASAP

---------- Post updated at 10:22 AM ---------- Previous update was at 09:03 AM ----------

Hi Ahamad, Thank you. The code worked.
But it changed other lines too...
for eg.
05:15-23:59; 05:15-21:00; 11:00-18:00; RCMAK_C_C; RetCntMake_C ; <qb:ErrorStatus>S</qb:ErrorStatus>
I want it to change for the above mentioned 3 lines only. Coz the file contains around 30 such entries. Any method to make it possible?

Whats the position of these lines?
If they are the first 3 entries then try this

Code:

awk 'NR<=3{split($5,arr,"_");sub(";","_"arr[2]";",$4);print}' file

regards,
Ahamed

Hi Ahamed,
The position of these lines is 16,17,18 in the file.

Regards,
Sam