Essential Linux Command Toolkit for Everyday Use

This compilation is designed to be a handy reference for common Linux commands, helping both new and seasoned users navigate various system tasks with ease.

Systemd

Systemd, the system and service manager for Linux, executes configuration files found in /etc/systemd/system during startup.

• Key Systemd Commands

  systemctl enable httpd
  systemctl start httpd
  systemctl status httpd
  systemctl stop httpd
  systemctl kill httpd
  systemctl restart httpd
  

Nohup

The nohup command is used to run another command without being affected by hangups. It writes to nohup.out only if the output is not redirected elsewhere.

nohup command >/dev/null 2>&1

To run the command in the background, add an ampersand at the end:

nohup command >/dev/null 2>&1 &

rc.local

This feature allows you to automatically run commands at system startup.

• Editing or Creating /etc/rc.local

  #!/bin/sh -e
  # [Additional script comments and structure]
  exit 0
  EOF
  

• Applying the Changes

  chmod +x /etc/rc.local
  systemctl daemon-reload
  systemctl enable rc-local
  systemctl start rc-local
  

Network Optimization

Optimizing network settings can significantly enhance system performance.

• Editing /etc/sysctl.conf

  s.file-max = 1000000
  fs.inotify.max_user_instances = 8192
  net.ipv4.tcp_syncookies = 1
  net.ipv4.tcp_fin_timeout = 30
  net.ipv4.tcp_tw_reuse = 1
  net.ipv4.ip_local_port_range = 1024 65000
  net.ipv4.tcp_max_syn_backlog = 16384
  net.ipv4.tcp_max_tw_buckets = 6000
  net.ipv4.route.gc_timeout = 100
  net.ipv4.tcp_syn_retries = 1
  net.ipv4.tcp_synack_retries = 1
  net.core.somaxconn = 32768
  net.core.netdev_max_backlog = 32768
  net.ipv4.tcp_timestamps = 0
  net.ipv4.tcp_max_orphans = 32768
  net.ipv4.conf.all.route_localnet=1
  net.ipv4.ip_forward = 1
  net.ipv4.tcp_no_metrics_save=1
  net.ipv4.tcp_ecn=0
  net.ipv4.tcp_frto=0
  net.ipv4.tcp_fastopen=3
  net.ipv4.tcp_mtu_probing=0
  net.ipv4.tcp_rfc1337=0
  net.ipv4.tcp_sack=1
  net.ipv4.tcp_fack=1
  net.ipv4.tcp_window_scaling=1
  net.ipv4.tcp_adv_win_scale=1
  net.ipv4.tcp_moderate_rcvbuf=1
  net.ipv4.tcp_rmem=40960 873800 167772160
  net.ipv4.tcp_wmem=40960 163840 167772160
  net.core.rmem_max=167772160
  net.core.wmem_max=167772160
  net.ipv4.udp_rmem_min=81920
  net.ipv4.udp_wmem_min=81920
  net.core.default_qdisc=fq
  net.ipv4.tcp_congestion_control=bbr
  

• Applying the New Configuration

  sysctl --system
  

This collection serves as a quick reference to efficiently manage and optimize Linux systems using straightforward commands and configurations.