I have this line:

08:30:02.480507 IP > 59865 [1au] A? click.em.redbox.com. (48)

I need to cut out the ".480507" in the timestamp so the line looks like this:

08:30:02 IP > 59865 [1au] A? click.em.redbox.com. (48)

I've fumbled around with several awk and cut statements but to no avail. I'd like to find an awk one liner but sed may be a better solution for this. I just don't know quite enough about either one when it comes to cutting in this fashion.

NOTE: This is an example, and the portion of the timestamp I need to cut out will not be the same, as I need to perform this action on a number of lines all with different timestamps.

3 Answers 3


I would use awk

awk --posix '{ gsub(/\.[[:digit:]]{6}/, "", $1); print }' filename

Will target the first field (space delimited) and search for a . followed by 6 numbers and empty it out.


With awk probably the simplest way is to do a regular expression substitution on the first whitespace-separated field, replacing everything from the period to the end of the field:

awk '{sub(/\..*/,"",$1)}1' somefile
  • Yes! exactly what I needed.
    – user53029
    Jun 21, 2016 at 14:52

with GNU sed

sed -r 's/^([^.]+)\.[0-9]+ /\1 /' filename
  • ^([^.]+) capture starting string upto first dot character
  • \.[0-9]+ match dot character followed by more than 1 digit characters

and if number of characters is consistent as given in the example,

sed -r 's/^(.{8}).{7} /\1 /' filename

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