journalctl tail and cheatsheet

Chưa phân loại
journalctl is a fancy new service in linux distributions, such as Ubuntu, Debian, CentOS and others, that wraps and abstracts the system log into a command line interface tool making it easier to find what you are looking for. The data is structured and indexed so its not like you are searching plain text files using grep, you have much more advanced searching and finding capabilities. You can use the journalctl command to print all the system logs, you can query it with a finer grained query, and sometimes you just want to TAIL the system logs to watch the system live as it operates. The –follow flag is used for the tail operation.

TL;DR : run journalctl -f

-f is short option for –follow. You can think of running journalctl -f as doing a tail operation on the system log.

journalctl cheatsheet

-a or –all

Show all characters, even long and unprintable lines and characters

-f or –follow

Like a tail operation for viewing live updates

-e or –page-end

Jump to the end of the log

-n or –lines=

Show the most recent n number of log lines

-o or –output=

Customizable output formatting. See man page for formatting options. Some examples include journalctl -o verbose to show all fields, journalctl -o cat to show compact terse output, journalctl -o json for JSON formatted output.

-x or –catalog

Explain the output fields based on metadata in the program

-q or –quiet

suppress warnings or info messages

-m or –merge

merge based on time local and remote entries


Print out the bootids which can be later used in filtering from time of a specific bootid

-b [ID][±offset]

Filter only based on the specified boot

-k or –dmesg

Filter only kernel messages

-g or –grep

Filter based on perl-compatible regular expressions for specific text


do case insensitive searching

-S, –since=, -U, –until=

Search based on a date. “2019-07-04 13:19:17”, “00:00:00”, “yesterday”, “today”, “tomorrow”, “now” are valid formats. For complete time and date specification, see systemd.time(7)


Show system messages only


Show user messages only


Shows space used by this log system

The journalctl system takes system logging to the next level. To see all the options be sure to read the man page. I hope this cheat sheet helps you get started with some quick options.

ONET IDC thành lập vào năm 2012, là công ty chuyên nghiệp tại Việt Nam trong lĩnh vực cung cấp dịch vụ Hosting, VPS, máy chủ vật lý, dịch vụ Firewall Anti DDoS, SSL… Với 10 năm xây dựng và phát triển, ứng dụng nhiều công nghệ hiện đại, ONET IDC đã giúp hàng ngàn khách hàng tin tưởng lựa chọn, mang lại sự ổn định tuyệt đối cho website của khách hàng để thúc đẩy việc kinh doanh đạt được hiệu quả và thành công.
Bài viết liên quan

Install Lightworks Non-Linear Editing Software on CentOS, RHEL, Ubuntu

Lightworks is a full-featured non-linear editing app with all the power, performance and features you would expect. It supports...

Top 5 Lightweight Web Browsers for Linux

Various Linux distributions provide a number of lightweight browsers that can easily run without eating up too much of...

Top 10 PDF Readers on Linux

The popularity of Portable Document Format (PDF) files increased drastically in recent years. Being one of the most secure...
Bài Viết

Bài Viết Mới Cập Nhật


Mua Proxy v6 US Private chạy PRE, Face, Insta, Gmail

Mua shadowsocks và hướng dẫn sữ dụng trên window

Tại sao Proxy Socks lại được ưa chuộng hơn Proxy HTTP?

Mua thuê proxy v4 nuôi zalo chất lượng cao, kinh nghiệm tránh quét tài khoản zalo