I keep a logfile of a program's output. The trouble is sometimes errors occur dumping very long lines of 7bit ascii data(encoded binary) I don't care to keep. These lines can be 200KB+ long before reaching a newline.
What might be a short, pipeable way eg. with
sed to change only lines exceeding 250 characters long, by keeping only the first 80 and last 40 characters of that line, possibly replacing the middle with only a _?