ubuntu 环境变量配置 并立即生效

Ubuntu Linux系统包含两类环境变量：系统环境变量和用户环境变量。系统环境变量对所有系统用户都有效，用户环境变量仅仅对当前的用户有效。

环境变量

用户环境变量通常被存储在下面的文件中：

    ~/.profile

    ~/.bash_profile 或者 ~./bash_login

    ~/.bashrc


系统环境变量

系统环境变量一般保存在下面的文件中：

    /etc/environment

    /etc/profile

    /etc/bash.bashrc

/etc/profile和 /etc/bash.bashrc在Ubuntu 10.0版本中不推荐使用。

加入环境变量

如想将一个路径加入到$PATH中，可以像下面这样做（修改用户环境变量 .bashrc）：

    
终端执行$ gedit ~/.bashrc

在里面加入:
#set android sdk
export SDK_ROOT=/home/jianjie/Android/adt-bundle-linux-x86-20131030/sdk
export PATH=$PATH:$SDK_ROOT/tools:$SDK_ROOT/platform-tools

#set android ndk
export NDK_ROOT=/home/jianjie/Android/android-ndk-r9b
export PATH=$PATH:$NDK_ROOT

#set eclipse
export ECLIPSE=/home/jianjie/Android/adt-bundle-linux-x86-20131030/eclipse
export PATH=$PATH:$ECLIPSE

你可以自己加上指定的多个路径，中间用冒号隔开。环境变量更改后，在用户下次登陆时生效，

如果想立刻生效，则可执行下面的语句：   

终端执行 $source ~/.bashrc

我的.bashrc文件如下：

# ~/.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[ -z "$PS1" ] && return# don't put duplicate lines or lines starting with space in the history.# See bash(1) for more optionsHISTCONTROL=ignoreboth# append to the history file, don't overwrite itshopt -s histappend# for setting history length see HISTSIZE and HISTFILESIZE in bash(1)HISTSIZE=1000HISTFILESIZE=2000# check the window size after each command and, if necessary,# update the values of LINES and COLUMNS.shopt -s checkwinsize# If set, the pattern "**" used in a pathname expansion context will# match all files and zero or more directories and subdirectories.#shopt -s globstar# make less more friendly for non-text input files, see lesspipe(1)[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"# set variable identifying the chroot you work in (used in the prompt below)if [ -z "$debian_chroot" ] && [ -r /etc/debian_chroot ]; then    debian_chroot=$(cat /etc/debian_chroot)fi# set a fancy prompt (non-color, unless we know we "want" color)case "$TERM" in    xterm-color) color_prompt=yes;;esac# uncomment for a colored prompt, if the terminal has the capability; turned# off by default to not distract the user: the focus in a terminal window# should be on the output of commands, not on the prompt#force_color_prompt=yesif [ -n "$force_color_prompt" ]; then    if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then# We have color support; assume it's compliant with Ecma-48# (ISO/IEC-6429). (Lack of such support is extremely rare, and such# a case would tend to support setf rather than setaf.)color_prompt=yes    elsecolor_prompt=    fifiif [ "$color_prompt" = yes ]; then    PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ 'else    PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ 'fiunset color_prompt force_color_prompt# If this is an xterm set the title to user@host:dircase "$TERM" inxterm*|rxvt*)    PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"    ;;*)    ;;esac# enable color support of ls and also add handy aliasesif [ -x /usr/bin/dircolors ]; then    test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"    alias ls='ls --color=auto'    #alias dir='dir --color=auto'    #alias vdir='vdir --color=auto'    alias grep='grep --color=auto'    alias fgrep='fgrep --color=auto'    alias egrep='egrep --color=auto'fi# some more ls aliasesalias ll='ls -alF'alias la='ls -A'alias l='ls -CF'# Add an "alert" alias for long running commands.  Use like so:#   sleep 10; alertalias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\''s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\'')"'# Alias definitions.# You may want to put all your additions into a separate file like# ~/.bash_aliases, instead of adding them here directly.# See /usr/share/doc/bash-doc/examples in the bash-doc package.if [ -f ~/.bash_aliases ]; then    . ~/.bash_aliasesfi# enable programmable completion features (you don't need to enable# this, if it's already enabled in /etc/bash.bashrc and /etc/profile# sources /etc/bash.bashrc).if [ -f /etc/bash_completion ] && ! shopt -oq posix; then    . /etc/bash_completionfi#set android sdkexport SDK_ROOT=/home/jianjie/Android/adt-bundle-linux-x86-20131030/sdkexport PATH=$PATH:$SDK_ROOT/tools:$SDK_ROOT/platform-tools#set android ndkexport NDK_ROOT=/home/jianjie/Android/android-ndk-r9bexport PATH=$PATH:$NDK_ROOT#set eclipseexport ECLIPSE=/home/jianjie/Android/adt-bundle-linux-x86-20131030/eclipseexport PATH=$PATH:$ECLIPSE

系统环境变量

打开终端并输入：
sudo gedit /etc/environment
2
输入用户密码。这时输入的密码是不可见的。
3
如图，在PATH="...."的末尾处添加：
：/opt/EmbedSky/4.3.3/bin
其中/opt/EmbedSky/4.3.3/bin为你自己需要设置的环境变量路径

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/home/proud/Android/adt-bundle-linux-x86-20140321/sdk/platform-tools"

你可以自己加上指定的多个路径，中间用冒号隔开。环境变量更改后，在用户下次登陆时生效，

如果想立刻生效，则可执行下面的语句：    

终端执行 $source/etc/environment

也可修改
然后执行$sudo gedit /etc/profile

配置同用户环境变量相同