Linux Learning Path 4-bash environment configuration

Bash Environment Configuration

Profiles : divided by effective scope, two categories:

Global configuration file:/ETC/PROFILE,/ETC/PROFILE.D/*.SH,ETC/BASHRC

Personal configuration file: ~/.BASH_PROFILE,~/.BASHRC

Classification by function: two types:

profile class: Interactive login ( i.e. login or su-username directly via the terminal)

/etc/profile,/etc/profile.d/*.sh,~/.bash_profile

function: 1. Define environment variables, such as PATH,PS1 2. Run a command or script

BASHRC class: Non-interactive login (Command window open under graphical interface, execute script, su username)

/etc/bashrc,~/.bashrc

function: 1. Define command Aliases 2. Define Local variables

configuration file Action order:

Interactive login:/etc/profile,/etc/profile.d/*.sh->~/.bash_profile, ~/.BASHRC,/etc/bashrc< /c7>

non-interactive login: ~/.BASHRC---/ETC/BASHRC->/etc/profile.d/*.sh

How does the configuration file change?

2. Re-Login

3. Lets the shell process reread the specified configuration file, source or. This way, but there will be some side effects

   Bash the variables in :

   Type:

   Environment variables: scope current shell process and its child processes

   local variable: scope current shell process

   Local variables: scoped only to a snippet of code in the current shell process (usually a function context)

   Position variable: $ $, $

   Special variables: $?

   How variables are defined:

   Bash built-in variables: can be called directly, built in a number of environment variables, such as Path

   Custom variable: variable assignment: variable name = value

   Bash Weak type:

   When a variable stores data, it is written by default, and any variable can be directly referenced without being declared;

   to define a local variable:

   Name=value

   View: Set

   Define environment variables:

   Export Name=value

   Declare-x Name=value

   View variables: env, printenv, export

   undo variable: Unsetname

   reference variable: ${name}, $name

   Bash the reference symbol in:

   "': strong references, variable substitution does not occur

        "" : Weak references

        ``: Command Reference

This article is from the "naïve Little Comrade" blog, please be sure to keep this source http://dengxi.blog.51cto.com/4804263/1691234

Linux Learning Path 4-bash environment configuration