Batch Script to Read Line by line of text and export.

Hi, I have a large text file, how I write a batch script to read line by line and when it find certain words it will export the whole line in a file. For example I have big.txt which includes in it: Customet Name: Bla1 Part Number: Bla1 Date of Purchase: Bla1 Billing: Bla1 Customet Name: Bla2 Part Number: Bla2 Date of Purchase: Bla2 Billing: Bla1 Customet Name: Bla3 Part Number: Bla3 Date of Purchase: Bla3 Billing: Bla3 So on......its a large file like this. I want a script that withh read each line and only when it finds a string "Customet Name: and "Part Number::" put them in a out.text file like this: Customet Name: Bla1 Part Number: Bla1 Customet Name: Bla2 Part Number: Bla2 Customet Name: Bla3 Part Number: Bla3 Thank you.