关于~/.bash profile、~/.bashrc、/etc/profile、/etc/profile.d的关系

网上关于这些文件的关系描述比较杂，而且有的似乎写错了。

本文在单纯读shell命令的情况下cv，仅为记录

首先大前提是，这些文件都是在bash下才会被load，其他shell不一定(例如sh就没效果)

个人home目录下，如果是采用useradd新建的用户和用户目录，默认文件是从/etc/skel/ 拷贝生成的

可以通过useradd -k 或者 useradd --skel 指定 【use this alternative skeleton directory】

[app@36785f69147e ~]$ ls -a ~/.
.  ..  .bash_history  .bash_logout  .bash_profile  .bashrc
[app@36785f69147e ~]$ ls /etc/skel/ -a
.  ..  .bash_logout  .bash_profile  .bashrc

用户进入bash环境以后【交互式login 和 交互式 non-login有差别】

首先执行的是 .bash_profile

在Centos 7下，一般.bash_profile是这样定义的

# cat ~/.bash_profile
# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
	. ~/.bashrc
fi

# User specific environment and startup programs

PATH=$PATH:$HOME/bin

export PATH

从中可以看出，~/.bashrc 是.bash_profile 调用执行起来的

# cat ~/.bashrc
# .bashrc

# User specific aliases and functions

alias rm='rm -i'
alias cp='cp -i'
alias mv='mv -i'

# Source global definitions
if [ -f /etc/bashrc ]; then
	. /etc/bashrc
fi

可以看出 /etc/bashrc 反而是 ~/.bashrc 调用执行起来的

# cat /etc/bashrc
# /etc/bashrc

# System wide functions and aliases
# Environment stuff goes in /etc/profile

# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.

# are we an interactive shell?
if [ "$PS1" ]; then
  if [ -z "$PROMPT_COMMAND" ]; then
    case $TERM in
    xterm*|vte*)
      if [ -e /etc/sysconfig/bash-prompt-xterm ]; then
          PROMPT_COMMAND=/etc/sysconfig/bash-prompt-xterm
      elif [ "${VTE_VERSION:-0}" -ge 3405 ]; then
          PROMPT_COMMAND="__vte_prompt_command"
      else
          PROMPT_COMMAND='printf "\033]0;%s@%s:%s\007" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
      fi
      ;;
    screen*)
      if [ -e /etc/sysconfig/bash-prompt-screen ]; then
          PROMPT_COMMAND=/etc/sysconfig/bash-prompt-screen
      else
          PROMPT_COMMAND='printf "\033k%s@%s:%s\033\\" "${USER}" "${HOSTNAME%%.*}" "${PWD/#$HOME/~}"'
      fi
      ;;
    *)
      [ -e /etc/sysconfig/bash-prompt-default ] && PROMPT_COMMAND=/etc/sysconfig/bash-prompt-default
      ;;
    esac
  fi
  # Turn on parallel history
  shopt -s histappend
  history -a
  # Turn on checkwinsize
  shopt -s checkwinsize
  [ "$PS1" = "\\s-\\v\\\$ " ] && PS1="[\u@\h \W]\\$ "
  # You might want to have e.g. tty in prompt (e.g. more virtual machines)
  # and console windows
  # If you want to do so, just add e.g.
  # if [ "$PS1" ]; then
  #   PS1="[\u@\h:\l \W]\\$ "
  # fi
  # to your custom modification shell script in /etc/profile.d/ directory
fi

if ! shopt -q login_shell ; then # We're not a login shell
    # Need to redefine pathmunge, it get's undefined at the end of /etc/profile
    pathmunge () {
        case ":${PATH}:" in
            *:"$1":*)
                ;;
            *)
                if [ "$2" = "after" ] ; then
                    PATH=$PATH:$1
                else
                    PATH=$1:$PATH
                fi
        esac
    }

    # By default, we want umask to get set. This sets it for non-login shell.
    # Current threshold for system reserved uid/gids is 200
    # You could check uidgid reservation validity in
    # /usr/share/doc/setup-*/uidgid file
    if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then
       umask 002
    else
       umask 022
    fi

    SHELL=/bin/bash
    # Only display echos from profile.d scripts if we are no login shell
    # and interactive - otherwise just process them to set envvars
    for i in /etc/profile.d/*.sh; do
        if [ -r "$i" ]; then
            if [ "$PS1" ]; then
                . "$i"
            else
                . "$i" >/dev/null
            fi
        fi
    done

    unset i
    unset -f pathmunge
fi
# vim:ts=4:sw=4

而 /etc/profile.d/*.sh 或者 /etc/profile.d/sh.local 是 /etc/bashrc 执行调用起来的(又被调用了一次)

# cat /etc/profile
# /etc/profile

# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc

# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.

pathmunge () {
    case ":${PATH}:" in
        *:"$1":*)
            ;;
        *)
            if [ "$2" = "after" ] ; then
                PATH=$PATH:$1
            else
                PATH=$1:$PATH
            fi
    esac
}


if [ -x /usr/bin/id ]; then
    if [ -z "$EUID" ]; then
        # ksh workaround
        EUID=`/usr/bin/id -u`
        UID=`/usr/bin/id -ru`
    fi
    USER="`/usr/bin/id -un`"
    LOGNAME=$USER
    MAIL="/var/spool/mail/$USER"
fi

# Path manipulation
if [ "$EUID" = "0" ]; then
    pathmunge /usr/sbin
    pathmunge /usr/local/sbin
else
    pathmunge /usr/local/sbin after
    pathmunge /usr/sbin after
fi

HOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=1000
if [ "$HISTCONTROL" = "ignorespace" ] ; then
    export HISTCONTROL=ignoreboth
else
    export HISTCONTROL=ignoredups
fi

export PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL

# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; then
    umask 002
else
    umask 022
fi

for i in /etc/profile.d/*.sh /etc/profile.d/sh.local ; do
    if [ -r "$i" ]; then
        if [ "${-#*i}" != "$-" ]; then
            . "$i"
        else
            . "$i" >/dev/null
        fi
    fi
done

unset i
unset -f pathmunge

export JAVA_HOME=/usr/java/jdk1.8.0_192
export PATH=$PATH:$JAVA_HOME/bin:$JAVA_HOME/jre/bin
export CLASSPATH=.:$JAVA_HOME/lib:$JAVA_HOME/jre/lib:$CLASSPATH


export HISTORY_FILE=/var/log/usermonitor.log
export PROMPT_COMMAND='{ date "+%y-%m-%d %T ##### $(who am i |awk "{print \$1\" \"\$2\" \"\$5}")  #### $(history 1 | { read x cmd; echo "$cmd"; })"; } >>$HISTORY_FILE'
export HISTTIMEFORMAT=" $(who am i |awk "{print \$1\" \"\$5}")  |  %F  | %T | "

所以猜测调用顺序为 bsah -> /etc/profile -> /etc/profile.d/*.sh 或者 /etc/profile.d/sh.local -> ~/.bash_profile -> ~/.bashrc -> /etc/bashrc -> /etc/profile.d/*.sh

.bash_logout在退出shell时被读取