ubuntu下关于profile和bashrc中环境变量的理解（转）

cat /etc/profile
cat /etc/bash.bashrc
cat ~/.profile
cat ~/.bashrc

blogger="piligrimHui" 这样定义的为局部变量
export blogger="pilgrimHui"这样定义的为全局变量（export这个变量，则升级为全局变量）

# parent.sh
#!/bin/bashpid="parent"
sh child.sh
echo "父shell访问子shell的cid:$cid"

# child.sh
#!/bin/bashecho "子shell访问父shell的pid:$pid"
cid="child"

sh parent.sh子shell访问父shell的pid:
父shell访问子shell的cid:

# parent.sh
#!/bin/bashexport name="parent"
echo "父shell的name:$name"
sh child.sh
echo "子shell修改name之后，父shell的name:$name"
echo "父shell访问子shell定义的nickName:$nickName"

# child.sh
#!/bin/bashecho "子shell的name:$name"
name="child"
echo "子shell修改name后，子shell的name:$name"
nickName="baby"

sh parent.sh父shell的name:parent
子shell的name:parent
子shell修改name后，子shell的name:child
子shell修改name之后，父shell的name:parent
父shell访问子shell定义的nickName:

# /etc/profile: system-wide .profile file for the Bourne shell (sh(1))
# and Bourne compatible shells (bash(1), ksh(1), ash(1), ...).if [ "$PS1" ]; then
if [ "$BASH" ] && [ "$BASH" != "/bin/sh" ]; then
# The file bash.bashrc already sets the default PS1.
# PS1='\h:\w\$ '
if [ -f /etc/bash.bashrc ]; then
. /etc/bash.bashrc
fi
else
if [ "`id -u`" -eq 0 ]; then
PS1='# '
else
PS1='$ '
fi
fi
fiif [ -d /etc/profile.d ]; then
for i in /etc/profile.d/*.sh; do
if [ -r $i ]; then
. $i
fi
done
unset i
fi

# ~/.profile: executed by the command interpreter for login shells.
# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
# exists.
# see /usr/share/doc/bash/examples/startup-files for examples.
# the files are located in the bash-doc package.# the default umask is set in /etc/profile; for setting the umask
# for ssh logins, install and configure the libpam-umask package.
#umask 022# if running bash
if [ -n "$BASH_VERSION" ]; then
# include .bashrc if it exists
if [ -f "$HOME/.bashrc" ]; then
. "$HOME/.bashrc"
fi
fi# set PATH so it includes user's private bin directories
PATH="$HOME/bin:$HOME/.local/bin:$PATH"

# System-wide .bashrc file for interactive bash(1) shells.# To enable the settings / commands in this file for login shells as well,
# this file has to be sourced in /etc/profile.# If not running interactively, don't do anything
[ -z "$PS1" ] && return...

# ~/.bashrc: executed by bash(1) for non-login shells.
# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
# for examples# If not running interactively, don't do anything
case $- in
*i*) ;;
*) return;;
esac...# some more ls aliases
alias ll='ls -alF'
alias la='ls -A'
alias l='ls -CF'

echo $PATH # 查看环境变量PATH