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
make install [DESTDIR=] [PREFIX=/usr/local] [MANPREFIX=PREFIX/man]
make uninstall [DESTDIR=] [PREFIX=/usr/local] [MANPREFIX=PREFIX/man]
Sijmen J. Mulder (ik@sjmulder.nl)