log-gap

log-gap is a simple python script that inspects syslog-formatted logfiles, and reports any time gaps. These can be used to detect the time of a system crash or hibernation, even in a busy (but single-host) log.

Usage is like:

$ ./log-gap --help
below cmd output started 2021 Sat Jan 16 10:15:20 AM PST
Usage: ./log-gap --gap-duration 300 --both -- file1 file2.gz ... file3
    The units on --gap-duration are seconds.
    --both to output the "before gap" and "after gap" lines, separated by a blank line

EG:

$ ./log-gap --gap-duration $((30*60)) --both /var/log/syslog*
below cmd output started 2021 Sat Jan 16 10:17:17 AM PST
Jan 10 16:23:00 zareason2 systemd[1]: Starting Network Manager Script Dispatcher Service...
Jan 10 16:53:01 zareason2 NetworkManager[802]:   [1610326381.0866] dhcp6 (enp2s0):   address 2600:1700:3610:7150::34

Jan 12 08:23:05 zareason2 systemd[1]: Starting Network Manager Script Dispatcher Service...
Jan 12 08:53:06 zareason2 NetworkManager[802]:   [1610470386.0744] dhcp6 (enp2s0):   preferred_lft 3600

Jan 13 16:23:09 zareason2 systemd[1]: Starting Network Manager Script Dispatcher Service...
Jan 13 16:53:10 zareason2 NetworkManager[802]:   [1610585590.0733] dhcp6 (enp2s0):   valid_lft 3600

Hits: 1702
Timestamp: 2026-03-03 01:02:18 PST

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