Peace be unto you o enlightened ones.

I have a large text file with many (~64000) similar lines in it. I would like to create a new file, differing from the original one in the following way:

If a line in the original file has 188 characters, followed by 8 numbers, followed by 16 characters, the corresponding line in the new file must have the 8 numbers replaced with 20020101, unless the original 8 numbers are 00000000, in which case the line is not copied into the new file.

I was thinking of something along the lines of:

perl -lne 'print unless /.{188}00000000.{16}/' original.txt > new.txt

This works for getting rid of the lines with 00000000 in them, but how do I adapt this in order to implement the replacement mentioned above?

Thanks in advance,

S

In reply to search and replace on a line by line basis by Anonymous Monk

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