What's the best command to use to change a timestamp to readable date when 'tail -f'-ing a log file?

Question

I have a program which logs like this:

1324218770.7644 INFO etc

What's the best Linux shell program to pipe that through to change the timestamps to a human readable format like Sun 18 Dec 2011 15:32:50 CET?

I can pipe like this through

| cut -f 1 -d\   | awk '{print strftime("%c",$1)}'

for the timestamps only, but how do I maintain the rest of the line?

Answer 1

just override $1, then print all line

$ echo '1324218770.7644 INFO etc' | awk '{$1=strftime("%c", $1); print}'

Answer 2

I assume that you want the date to be changed inline, printing the rest of the line as well. Try replacing field 1 with the output of strftime().

$ echo "1234218770.7644 INFO etc' | awk '{$1=strftime("%c", $1); print}'
Mon 09 Feb 2009 05:32:50 PM EST INFO etc