Bashrc and profile

Reading guide ： Interactive shell And non interactive shell; login shell and non-login shell

Interactive mode is shell Waiting for your input , And execute the order you submitted . This pattern is called interactive because shell Interact with users . This pattern is also familiar to most users ： Sign in 、 Execute some orders 、 Sign off . When you sign back ,shell It's over . shell It can also run in another mode ：

Non interactive mode . In this mode ,shell Don't interact with you , Instead, read the commands stored in the file , And execute them . When it reads to the end of the file ,shell It's over .

 

One 、bashrc And profile Are used to save the user's environment information . Let's go through each of these ：

/etc/profile（ overall situation , For interactive login shell）： This file sets the environment information for each user of the system , When the first user logs in , The document is executed . And from /etc/profile.d Directory of configuration files shell Set up .

When the /etc/profile If there is any modification, you must restart the modification to take effect , This change takes effect for every user .

 

/etc/pro.d：.d Presentation directory , The directory contains some startup scripts required by the application , It includes color 、 Language 、less、vim And which Some additional settings of the command . The reason why these script files can be executed automatically , Because in /etc/profile Use one for Loop statements to call these scripts . These script files are used to set some variables and run some initialization processes .

#  for example ：
# The default umask is now handled by pam_umask.
# See pam_umask(8) and /etc/login.defs.

if [ -d /etc/profile.d ]; then              #  Judge /etc/profile.d  Is it a directory 
  for i in /etc/profile.d/*.sh; do       # If it's a directory , Go to this directory , Take out each shell Program 
    if [ -r $i ]; then                             # If it's time to shell It can be executed 
      . $i                                               #  Then execute it 
    fi
  done
  unset i
fi

 

/etc/bashrc（ overall situation , For non interactive non-loginshell）： For each run bash shell Of users executing this file . When bash shell When opened , The file is read （ There are some linux In version /etc There is no more bashrc file ）.

If you want to use it for all bash Users who modify a configuration and open it later bash You can modify this file if it takes effect , You don't need to restart to modify this file , Reopen a bash Effective .

 

~/.bash_profile（ Interactive 、login Way in bash function ）： Each user can use this file to input the shell Information , When the user logs in , The file is only executed once ！ By default , He sets some environment variables , Execute the user's .bashrc file .

This file is similar to /etc/profile, It also needs to be restarted to take effect ,/etc/profile Effective for all users ,~/.bash_profile Only valid for the current user .

 

~/.bashrc（ Interactive non-login Way in bash function ）： This file contains... For a specific user bash shell Of bash Information , When the user logs in and every time the new shell when , The file is read . Each user has one .bashrc file .

~/.bash_logout： Every time you exit the system ( sign out bash shell) when , Execute the document .

 

Two 、 similarities and differences ：

1、bashrc It will run automatically after the system starts .profile Only after the user logs in .

2、/etc/profile Variable set in etc ( overall situation ) Can work for any user , and ~/.bashrc Variable set in etc ( Local ) Can only inherit /etc/profile The variables in the , They are " Father and son " Relationship .

3、 After setting , It can be used source bashrc The command to update bashrc, You can also use source profile The command to update profile.

 

3、 ... and 、 Get a... When logging in shell Process time , There are three steps to read the environment profile

1、 The global environment variable profile is read in first /etc/profile, Then read the additional set document according to its content , Such as ：/etc/profile.d and /etc/inputrc

2、 Then according to different user accounts , Go to their home directory to read ~/.bash_profile, If this can't be read, read ~/.bash_login, This can't be read before ~/.profile, These three document settings are basically the same , Read has priority

3、 Then read according to the user account ~/.bashrc. as for ~/.profile And ~/.bashrc All of them have the function of personalized customization .
~/.profile You can set the exclusive path of this user , Environmental variables, etc , It can only be executed once when logging in
~/.bashrc It is also a user specific setting document , You can set the path , Command alias , Every time shell script It will be used once for the execution of