Mario Domgörgen
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dategrep - print lines matching a date range


  dategrep --start "12:00" --end "12:15" --format "%b %d %H:%M:%S" syslog
  dategrep --end "12:15" --format "%b %d %H:%M:%S" syslog
  dategrep --last-minutes 5 --format "%b %d %H:%M:%S" syslog
  dategrep --last-minutes 5 --format rsyslog syslog
  cat syslog | dategrep --end "12:15"


dategrep searches the named input files for lines matching a date range and prints them to stdout.

If dategrep works on a seekable file, it can do a binary search to find the first and last line to print pretty efficiently. dategrep can also read from stdin and compressed files, but it has to parse every single line until the end of the range for those.


--start|--from DATESPEC

Print all lines from DATESPEC inclusively. Defaults to Jan 1, 1970 00:00:00 GMT. See VALID-DATE-FORMATS for a list of possible formats for DATESPEC.

--end|--to DATESPEC

Print all lines until DATESPEC exclusively. Default to the current time. See VALID-DATE-FORMATS for a list of possible formats for DATESPEC.

--last-minutes MINUTES

Print all lines from MINUTES minutes ago until the beginning of the current minute. So if we have 19:25:43 and MINUTES is five, dategrep will print all lines from 19:20:00 to 19:24:59.

--format FORMAT

Defines a strftime-based FORMAT that is used to parse the input lines for a date. The first date found on a line is used. The list of possible escape sequences can be found under PRINTF DIRECTIVES.

This is a required parameter. Alternatively you can supply the format via the environment variable DATEGREP_DEFAULT_FORMAT.

Additionally, dategrep supports named formats:

  • rsyslog "%b %d %H:%M:%S"

  • apache "%d/%b/%Y:%T %z"


Print all lines between the start and end line even if they are not timestamped.

--blocksize SIZE

SIZE of the intervals used in the binary search. Defaults to the native blocksize of the file's filesystem or 8129.


Print lines sorted by timestamp even if the timestamps in the input files are overlapping.


Sort files in the order of the first line with a timestamp. For example: If you have a common logrotate configuration, you probably have files like syslog, syslog.1, syslog.2 etc. For dategrep to work we need those files in reverse order: syslog.2, syslog.1, syslog. This options handles that for you.

--configfile FILE

Reads configuration from FILE instead of ~/.dategreprc.


Shows a short help message


Shows the complete man page in your pager.


On startup dategrep reads a configuration file from $HOME/.dategreprc or the file specified by --configfile.

The file consists of sections and variables. A section begins with the name of the section in square brackets and continues until the next section begins. Section names are not case sensitive. Empty lines and lines with comments are skipped. Comments are started with a hash character. dategrep recognizes only one sections: Under formats you can list additional named formats.


  time = %H:%M:%S



Default for the --format parameter. The syntax is described there.


dategrep has only minimal support for compressed files. If any file in ARGV has an extension like .z,.gz,.bz2,.bz, dategrep will call zcat or bzcat respectively and read from it like from stdin.


It is possible to install this script via perl normal install routines.

  perl Build.PL
  ./Build install

Or you can use one of the two prebuild versions, which already include all or same of dategreps dependencies. Which to choose mainly depends on how hard it is for you to install Date::Manip. The small version is just 22.3KB big and includes all libraries except Date::Manip. The big one packs everything in a nice, neat package for you, but will cost you almost 10MB of disk space.

So, to install the big version you could just type:

  cp ~/bin/dategrep
  chmod +x ~/bin/dategrep

And for the small one (with the apt-get for Debian):

  cp ~/bin/dategrep
  chmod +x ~/bin/dategrep
  apt-get install libdate-manip-perl


dategrep expects the files to be sorted. If the timestamps are not ascending, dategrep might be exiting before the last line in its date range is printed.

Compressed files are just piped into dategrep via bzcat or zcat.



Copyright 2014 Mario Domgoergen <>

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

This program 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 General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <>.