journalctl: how to display colors in its output?

Question

The output of journalctl really looks messy without colors. Is it possible to add colors to its output? On my system it seems only important lines are highlighted. Even dmesg can output with color by adding the --color switch!

Answer 1

If the original daemon output is already colorized, but the colors are being lost when using journalctl, the --output cat option will restore them. See the manual for more details.

Answer 2

Install ccze, then use it like this:

journalctl -b -k -f | ccze [-A] [-o nolookups]

explanation:

 -A, --raw-ansi
        If one wants to enable raw ANSI color sequences instead of using curses, this option does just that.
 -o, --options OPTIONS...
        However,  lookups  is  an  option that might be better to disable. When on, ccze will try to look up usernames, service
        names, and lots of other stuff, which will slow down coloring a great deal. If one is piping a long log  through  ccze,
        this option might be turned off [nolookups]  to speed up the process.

Answer 3

The color support of journalctl is documented in man journalctl:

When outputting to a tty, lines are colored according to priority: lines of level ERROR and higher are colored red; lines of level NOTICE and higher are highlighted; other lines are displayed normally.

That's from systemd 229. As seen in the man page, There are no other built-in color controls for journalctl.

Answer 4

Seeking long for the answer, I actually figured out what works for me (with Rails logs and journalctl) – just add --all option.

journalctl -u puma --all

From manpage:

   -a, --all
      Show all fields in full, even if they include unprintable characters 
      or are very long. By default, fields with unprintable characters 
      are abbreviated as "blob data". (Note that the pager may escape 
      unprintable characters again.)

Answer 5

I use ccze for all the logs.

Example for jornalctl with color.

journalctl -b -k -f | ccze
journalctl -b -k -f | ccze -A

Other examples.

tail -f /etc/nginx/logs/access.log | ccze
tail -f /etc/unbound/unbound.log | ccze

Exporting logs

to export the log to HTML and save it to /root/syslog.html:

ccze -h -o nolookups /root/syslog.html 

I hope you find it useful.

Answer 6

journalctl -u [your.service] -f -o cat | logalize

https://github.com/deponian/logalize

Answer 7

It gives color to log files and command outputs:

1. ccze -A </etc/nsswitch.conf | cat shows nsswitch.conf with colors, another way could be cat /etc/nsswitch.conf | ccze -A

2. tail -f /var/log/syslog | ccze dit to execute tail -f /var/log/syslog but here it shows with colors, another form could be ccze -A </var/log/syslog | less -R

3. ccze -A </home/pepe.txt | less -R idem. To run less /home/pepe.txt but displays it with colors.

4. ccze -h -o nolookups </var/log/syslog> /root/syslog.html exports the log to HTML and saves it to /root/syslog.html.