Linux Admin Docker

Create sudo user with bash and homedir:
useradd -m -d /home/testuser/ -s /bin/bash -G sudo testuser



######################################################### FILES
Truncate file
truncate -s 0 /var/log/syslog

Find folders and set access for them:
sudo find . -type d -exec chmod 755 {} +

Get/Delete files by mask:
Check: find . -name "*.bak" -type f
Delete: find . -name "*.bak" -type f -delete

Remove *.gz files older than 1 day
find ./path_to_find -name "*.gz" -type f -mtime +1 -exec rm {} \;

Remove files by mask
find ./path_to_find -name "*.spec.ts" -type f -delete



######################################################## DISK
Disk Info:
sudo aprted -l
sudo df -h
sudo df -h --output=source,fstype,size,used,avail,pcent,target -x tmpfs -x devtmpfs

Show largest directorries in current path:
sudo du --max-depth=1 2> /dev/null | sort -n -r | head -n20

SSH keys
ssh-keygen -t rsa
~/.ssh/authorized_keys



######################################################## NETWORK
Show LISTEN ports
netstat -ntlp | grep LISTEN

#Show ports2
sudo iptables -t nat -L -n



######################################################## DOCKER
#Show all docker containers internal IP
#For common docker
docker inspect -f '{{.Name}} - {{.NetworkSettings.IPAddress }}' $(docker ps -aq)
#For docker-compose usage
docker inspect -f '{{.Name}} - {{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $(docker ps -aq)



######################################################## DATABASE
DB. Import big file by console
psql --host=127.0.0.1 --port=5432 --dbname=mycity --username=mycity --password -f /path_dump/dump.sql