From 04b59953f7ba2f5839bba54a14141a687545782e Mon Sep 17 00:00:00 2001 From: tactonbishop Date: Sun, 21 Aug 2022 09:00:05 +0100 Subject: [PATCH] Last Sync: 2022-08-21 09:00:05 --- Linux/journald.md | 48 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) diff --git a/Linux/journald.md b/Linux/journald.md index e69de29..f3a085e 100644 --- a/Linux/journald.md +++ b/Linux/journald.md @@ -0,0 +1,48 @@ +--- +categories: + - Linux +tags: [journal, systemd, sytems-programming] +--- + + +# `journald` + +`journald` is a program that comes as default with [systemd](/Linux/systemd.md). It is a service fror collecting and storing system-level log data. I keeps a track of all [kernel](/Operating_Systems/The_Kernel.md) processes. It is invaluable when tracing the source of problems and errors that may arise on the system level. It keeps a track of all kernal processes. + +![](/img/journald.png) + + +## `journalctl` + +We use `journalctl` to access the logs. The command by itself outputs the entire log which will be huge and hard to scroll through. We can refine the results with modifiers. + + +### View logs for a specific process with pid + +```bash +journalctl _PID=1234 +``` + +### View logs for a specific time period +This can be really helpful since you can bracket the most recent events which will be more memorable. + +```bash +journalctl -S -1h +``` + +### View logs for a specfic systemd unit +```bash +journalctl -u cronie.service +``` + +### View boot logs +```bash +journalctl -b +``` + +#### Identify specific boot + +```bash +journalctl --list-boots + +``` \ No newline at end of file