π subnode [[@karlicoss/linux]]
in π node [[linux]]
debugging:
profiling:
install build dependencies:
docker is excellent for quick sandboxes (just use
Table of Contents
- [[related]] [[infra]]
-
[[docker]] [[docker]]
[2018-06-15]
docker system prune
to cleanup[2021-01-12]
figuring out what takes disk spacedocker images | awk '{print $3}' | xargs docker inspect | less
[[docker]][2021-02-12]
Docker compose port mapping - Stack Overflow[2021-04-14]
apt-get clean and other strategies for keeping image size small? Β· Issue 35 Β· rocker-org/rocker [[docker]][2021-05-02]
Attach and Detach from Docker Container | HowToProgram [[docker]] [[drill]]
-
[[systemd]] [[systemd]]
- [debugging:
systemctl --failed
,journalctl
](#dbggngsystmctlfldjrnlctl TIDDLYLINK) - [profiling:
systemd-analyze blame
](#prflngsystmdnlyzblm TIDDLYLINK)
- [debugging:
- [[networking]] [[network]]
-
[[apt]]
- [install build dependencies:
sudo apt-get build-dep package
](#nstllblddpndncssdptgtblddppckg TIDDLYLINK)
- [install build dependencies:
- [[cron]] [[cron]]
-
[[sandboxing]] [[sandbox]]
- [docker is excellent for quick sandboxes (just use
ubuntu:latest
image or something)](#dckrsxcllntfrqcksndbxsjstsbntltstmgrsmthng TIDDLYLINK) [[docker]] - [
firejail
for network sandbox](#frjlfrntwrksndbx TIDDLYLINK) [[network]] [[testing]]
- [docker is excellent for quick sandboxes (just use
-
[[udev]] [[udev]]
- [
udevadm info /dev/sdc2
](#dvdmnfdvsdc TIDDLYLINK) [2019-03-07]
when you update rules filesudo udevadm control --reload-rules
[2019-03-07]
to trigger the target scriptsudo udevadm trigger
- [
[2017-05-08]
Gateway 0.0.0.0 means that the subnet is link-local i.e. there is no gateway involved, the packets are delivered directly to the target [[network]]- [[-----]]
[2018-06-08]
Linux ignores the setuid bit on all interpreted executables (i.e. executables starting with a#!
line).[2020-01-29]
linux - How to make htop sort by PID[2020-01-24]
logs - View stdout/stderr of systemd service [[systemd]][2020-01-29]
How to read memory usage in htop? - Server Fault [[drill]][2020-12-04]
linux - prevent system freeze/unresponsiveness due to swapping run away memory usage - Super User[2018-04-27]
guide to XKB- [[-]]
- [
whereis
command](#whrscmmnd TIDDLYLINK) [[habit]]
related [[infra]]
docker [[docker]]
[2018-06-15]
docker system prune
to cleanup
[2021-01-12]
figuring out what takes disk space docker images | awk '{print $3}' | xargs docker inspect | less
[[docker]]
[2021-02-12]
Docker compose port mapping - Stack Overflow
If you want to bind to the redis port from your nodejs container you will have to expose that port in the redis container:
version: '2'
services:
nodejs:
build:
context: .
dockerfile: DockerFile
ports:
- "4000:4000"
links:
- redis
redis:
build:
context: .
dockerfile: Dockerfile-redis
expose:
- "6379"
The expose tag will let you expose ports without publishing them to the host machine, but they will be exposed to the containers networks.
[2021-04-14]
apt-get clean and other strategies for keeping image size small? Β· Issue 35 Β· rocker-org/rocker [[docker]]
ok, so for debian/ubuntu images don't really need autoclean β it's already run automatically
[2021-05-02]
Attach and Detach from Docker Container | HowToProgram [[docker]] [[drill]]
In general, to detach from a Docker container and leave it running, we can use the CTRL-p CTRL-q key sequence.
systemd [[systemd]]
debugging: systemctl --failed
, journalctl
logs β for individual jobs you can see them via status (or sdj)
presistent is not showing anythin by default?
profiling: systemd-analyze blame
networking [[network]]
who uses local port
sudo ss -tulpn | grep 5060
sudo ss -anpt | grep 8640
testing if port is open
netcat -l 5559
one the other machine
echo "TEST" | netcat host 5559
[2020-06-15]
linux - Test if a port on a remote system is reachable (without telnet) - Super User
Nice and verbose! From the man pages.
Single port:
nc -zv 127.0.0.1 80
testing if port is open
apt
install build dependencies: sudo apt-get build-dep package
cron [[cron]]
[2018-02-26]
if cron fails to start a job, it will send the output to local mail
grep cron /var/log/syslog
tail -f /var/log/syslog | grep cron
[2018-05-10]
mail subject β use bash comment operator
*:* TestJob; cron command
mind the space after colon!
sandboxing [[sandbox]]
docker is excellent for quick sandboxes (just use ubuntu:latest
image or something) [[docker]]
firejail
for network sandbox [[network]] [[testing]]
- doesn't require root!
firejail --noprofile --net=none
udev [[udev]]
udevadm info /dev/sdc2
[2019-03-07]
when you update rules file sudo udevadm control --reload-rules
[2019-03-07]
to trigger the target script sudo udevadm trigger
[2017-05-08]
Gateway 0.0.0.0 means that the subnet is link-local i.e. there is no gateway involved, the packets are delivered directly to the target [[network]]
-----
[2018-06-08]
Linux ignores the setuid bit on all interpreted executables (i.e. executables starting with a #!
line).
ok apparently setuid shell scripts are quite riskyβ¦
[2020-01-29]
linux - How to make htop sort by PID
press > and select RES
[2020-01-24]
logs - View stdout/stderr of systemd service [[systemd]]
Note that using the standard logging mechanism like this will not create persistent logs by default. To do that, you'll need to create /var/log/journal, and then run sudo systemctl restart systemd-journald
[2020-01-29]
How to read memory usage in htop? - Server Fault [[drill]]
https://serverfault.com/questions/517483/how-to-read-memory-usage-in-htop
Hide user threads (shift + H) and close the process tree view (F5), t
[2020-12-04]
linux - prevent system freeze/unresponsiveness due to swapping run away memory usage - Super User
If a process demands a lot of memory, the system moves all other process to the swap file. Including it seems, necessary processes like the X11 server or the terminal.
[2018-04-27]
guide to XKB
-
whereis
command [[habit]]
π stoas
- public document at doc.anagora.org/linux
- video call at meet.jit.si/linux