linux notes

a collection of frequently-used linux operations.

ssh service

  • useradd -m [username], -m will automatically create new user folder in /home
  • passwd [username], configure password
  • usermod -s /bin/bash [username], change default login shell
    • cat /etc/passwd list all users
    • cat /etc/shells list all available shells
  • usermod -aG sudo pwxcoo,grant sudo privileges
    • groups check group of current user
  • in client,scp id_rsa.pub [username]@[server address]:/home/[username] transfer public key to server
  • back to server,mv id_rsa.pub .ssh/authorized_keys will be ok

nginx

  • sudo apt update
  • sudo apt install nginx
  • cd /etc/nginx/conf.d (NGINX site-specific configuration files are kept in /etc/nginx/conf.d)
  • simple template. example.com.conf

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    server {
    listen 80;
    server_name example.com;

    #charset koi8-r;
    #access_log /var/log/nginx/host.access.log main;

    location / {
    root /usr/share/nginx/html;
    index index.html index.htm;
    }

    #error_page 404 /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page 500 502 503 504 /50x.html;
    location = /50x.html {
    root /usr/share/nginx/html;
    }
    }
  • test nginx configration is ok

    • sudo nginx -t
    • sudo nginx -s reload

environment variables

linux will execute /etc/profile while booting up, this script will execute all script in /etc/profile.d, so add some scripts in /etc/profile.d will be easily maintained and convenient.

like jdk.sh, it will set environment variables for Java.

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export J2SDKDIR=/usr/lib/jvm/java-8-oracle
export J2REDIR=/usr/lib/jvm/java-8-oracle/jre
export PATH=$PATH:/usr/lib/jvm/java-8-oracle/bin:/usr/lib/jvm/java-8-oracle/db/bin:/usr/lib/jvm/java-8-oracle/jre/bin
export JAVA_HOME=/usr/lib/jvm/java-8-oracle
export DERBY_HOME=/usr/lib/jvm/java-8-oracle/db