Add a timestamp to every line of a stream
Switch branches/tags
Nothing to show
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Type Name Latest commit message Commit time
Failed to load latest commit information.


Add a timestamp to every line of a stream:

... | dated [-f format]


dated copies standard input to standard output, prepending the date and time to every line.

The -f option changes the prefix format string to format, which is passed to strftime(3). The default is "%x %X ": the local date notation, a space, the local time notation, and another space.

Note: there is no way to get subsecond precision, a limitation of strftime(3).


Watch a file with tail(1) and see when lines were added:

$ tail -f test.txt | dated
11/07/18 21:28:31 Hello
11/07/18 21:28:40 World!

Change the output format:

$ tail -f test.txt | dated -f "[%H:%M] "
[21:32] Hello
[21:33] World!


Should work on any Unix, including Linux and macOS.

Mac users can install from my Homebrew tap

brew install sjmulder/tap/dated

To compile, install and uninstal from source:

make install   [DESTDIR=] [PREFIX=/usr/local] [MANPREFIX=PREFIX/man]
make uninstall [DESTDIR=] [PREFIX=/usr/local] [MANPREFIX=PREFIX/man]


Copyright (c) 2018, Sijmen J. Mulder (

dated is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

dated is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with dated. If not, see