Extracting each line from a file and passing it as a variable to "foreach" loop

Question

Could somebody help me figure out a simple way of doing this using any script ? I will be running the script on Linux

1 ) I have a file1 which has the following lines :

 (Bank8GntR[3] | Bank8GntR[2] | Bank8GntR[1] | Bank8GntR[0] ),

 (Bank7GntR[3] | Bank7GntR[2] | Bank7GntR[1] | Bank7GntR[0] ),

 (Bank6GntR[3] | Bank6GntR[2] | Bank6GntR[1] | Bank6GntR[0] ),

 (Bank5GntR[3] | Bank5GntR[2] | Bank5GntR[1] | Bank5GntR[0] ),  

2 ) I need the contents of file1 to be modified as following and written to a file2

 (Bank15GntR[3] | Bank15GntR[2] | Bank15GntR[1] | Bank15GntR[0] ),

 (Bank14GntR[3] | Bank14GntR[2] | Bank14GntR[1] | Bank14GntR[0] ),

 (Bank13GntR[3] | Bank13GntR[2] | Bank13GntR[1] | Bank13GntR[0] ),

 (Bank12GntR[3] | Bank12GntR[2] | Bank12GntR[1] | Bank12GntR[0] ),

So I have to:

1. read each line from the file1,
2. use "search" using regular expression,
3. to match Bank[0-9]GntR,
4. replace \1 with "7 added to number matched",
5. insert it back into the line,
6. write the line into a new file.

Answer 1

How about something like this in Python:

# a function that adds 7 to a matched group.
# groups 1 and 2, we grabbed (Bank) to avoid catching the digits in brackets.
def plus7(matchobj):
  return '%s%d' % (matchobj.group(1), int(matchobj.group(2)) + 7)

# iterate over the input file, have access to the output file.
with open('in.txt') as fhi, open('out.txt', 'w') as fho:
  for line in fhi:
    fho.write(re.sub('(Bank)(\d+)', plus7, line))

Answer 2

Assuming you don't have to use python, you can do this using awk:

cat test.txt | awk 'match($0, /Bank([0-9]+)GntR/, nums) { d=nums[1]+7; gsub(/Bank[0-9]+GntR\[/, "Bank" d "GntR["); print }'

This gives the desired output.

The point here is that match will match your data and allows capturing groups which you can use to extract out the number. As awk supports arithmetic, you can then add 7 within awk and then do a replacement on all the values in the rest of the line. Note, I've assumed all the values in the line have the same digit in them.