BASH

 

 

(GNU) Bash

사용자로부터 명령어를 입력받아 해석, 번역, 실행시켜주는 인터페이스 역할을 함

 

 

 

 

 

 

 

 

 

 

System Account

• getent password

 

 

 

 

 

 

 

 

Environment Variable

• PATH
  PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin

 

• HOME
  HOME=/root

 

 

 

 

 

 

 

 

Environment Variable files

• /etc/profile
• bashrc

 

 

 

 

 

 

 

 

Set Environment Variable

• env
• set
• export

 

 

 

 

 

 

 

 

alias / source

• alias
• source/.

 

 

 

 

 

 

 

Shell Script

• assign variable
  A=1, b=1
  C="Shell Script"
  D=$A
  
• '
  A='Is /etc/profile'
  
  
• echo
  echo $A
  
  
• unset
  unset A
  
  
• expr
  expr 1 + 1, expr 2 \* 2, expr 4 / 2, expr 4 % 2
  A='expr 1 + 1'
  
  
• test, []
  test $A == $B
  echo $?
  
  [ $A == $B ]
  echo $?
  
  0: true, 1: false
  
  
• $?
  
• Relational Operators
  -rq, -ne, -gt, -lt, -ge, -le
  
  
• Boolean Operators
  !, -o, -a
  
  
• String Operators
  =, !=, -z, -n
  
  
• File Test Operators
  -b, -c, -d, -f, -g