Linux Command Environment Setup order

Turn http://blog.csdn.net/dingxy/article/details/4016383


The procedure to execute a file when logging on to Linux is as follows:

When you first log in to Linux, start the/etc/profile file, and then start one of the ~/.bash_profile, ~/.bash_login, or ~/.profile files in the user directory,



The order of execution is: ~/.bash_profile, ~/.bash_login, ~/.profile.

If the ~/.bash_profile file exists, the ~/.BASHRC file is typically executed.



Because the following code is commonly found in the ~/.bash_profile file:
If [-f ~/.BASHRC]; Then

. ./BASHRC

Fi

In ~/.BASHRC, the following code is generally available:
if [-F/ETC/BASHRC]; Then

. /bashrc

Fi

Therefore, ~/.BASHRC will call the/ETC/BASHRC file. Finally, when you exit the shell, the ~/.bash_logout file is also executed.

Order of execution:/etc/profile---(~/.bash_profile | ~/.bash_login | ~/.profile), ~/.BASHRC,/ETC/BASHRC, ~/.bash_lo Gout

For the scope of each file, the following instructions were found on the Web:

(1)/etc/profile: This file sets the environment information for each user of the system, and the file is executed when the user logs on for the first time. and collect the shell settings from the configuration file of the/ETC/PROFILE.D directory.

(2)/ETC/BASHRC: Executes this file for each user running the bash shell. When the bash shell is opened, the file is read.

(3) ~/.bash_profile: Each user can use this file to enter the shell information dedicated to their own use, when the user log on, the file is only executed once! By default, he sets some environment variables to execute the user's. bashrc file.

(4) ~/.BASHRC: This file contains bash information dedicated to your bash shell, which is read when you log in and every time you open a new shell.

(5) ~/.bash_logout: Executes the file each time it exits the system (exiting the bash shell). In addition, the variables set in/etc/profile (global) can be applied to any user, while the variables set in ~/.BASHRC, etc. (local) only inherit variables from/etc/profile, they are "parent-child" relationships.

(6) ~/.bash_profile is the interactive, login way into bash run ~/.BASHRC is the interactive non-login way into bash normally the two settings are roughly the same, so the former usually calls the latter.



The use of various environment variable settings files such as/etc/profile and/etc/environment


First add the export LANG=ZH_CN to/etc/profile, exit the system to log in again, login prompt display in English.


Delete the export lang=zh_cn in/etc/profile, add LNAG=ZH_CN to/etc/environment, exit the system to log in again, sign in prompt to display Chinese.


The user environment is established by always executing/etc/profile and then reading the/etc/environment. Why is it as different as the above?

The/etc/environment should be executed first and then executed/etc/profile.

/etc/environment is the environment that sets up the entire system, and/etc/profile is the environment for setting up all users, regardless of the logged-on user, which is related to the logged-on user.

The execution of the system application can be irrelevant to the user environment, but it is related to the system environment, so when you log in, you see the prompt information, such as date, time information display format is related to the system environment Lang, default Lang=en_us, if the system environment LANG=ZH_CN, The message is in Chinese, otherwise it is in English.


For a user's shell initialization, the/etc/profile is executed first, and then the file/etc/environment is read. The/etc/environment is performed first for the entire system. Do you understand that correctly?

/etc/enviroment--/etc/profile-$HOME/.profile--$HOME/.env (if present)

/etc/profile is the environment variable for all users


/etc/enviroment is the environment variable of the system


The order in which the shell reads the system when logging in should be
/etc/profile->/etc/enviroment-$HOME/.profile-$HOME/.env
The reason should be the difference between the user environment and the system environment described by JTW.

If the same variable has different values in the user environment (/etc/profile) and the system environment (/etc/environment), then the user environment should prevail.

Linux Command Environment Setup order