## Insert text before a line into multiple files

The stream editor sed inserts text before a specified pattern. sed -i '/pattern/i\inserted …

Times are stored internally by Excel as fractions of a 24-hour day, so that 12:00:00 would be stored as 0.5 and 18:00:00 as 0.75. Consequently, to convert a time to seconds, you must multiply by the number of seconds in a day - it is easier to remember this as *24*60*60 rather than the actual number (86400).

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