Linux Basic Concepts

1. User Category:
Admin: 0
Normal Users: 1-65535
System User: 1-499 "dedicated to running background processes, no login required, no user association"
General User: 500-60000 "a normal user created by an administrator for daily work and cannot manage the system"

2. From the user perspective, the shell type:
① Log-in shell
Log in normally via a terminal
Su-username
Su-l Usernaem
② Non-logon shell
Su USERNAME
Command window open under graphical terminal
Shell scripts that are executed automatically
3. Bash configuration file:
① Global Configuration
/etc/profile,/etc/profile.d/*.sh,/etc/bashrc
② Personal Configuration
~/.bash_profile,~/.bashrc
Profile type file: ① set environment variable ② Run command or script
BASHRC type file: ① set local variable ② set command alias
4. How does the login shell read the configuration file?
/etc/profile--/etc/profile.d/*.sh--and ~/.bash_profiel--~/.BASHRC--/ETC/BASHRC
5. How does the non-login shell read the configuration file?
~/.BASHRC--/ETC/BASHRC-/etc/profile.d/*.sh

Linux Basic Concepts