技能 |【點滴知識】 Linux平臺(bash) 檢視/設定/刪除 環境變數的方法。

1. 檢視環境變數

 

(1) export                                      /* 檢視當前系統中所有的環境變數*/

 

[示例]:

root@wolfrun-desktop: /home# export 

 

declare -x ARCH="arm"
declare -x CLASSPATH="/usr/local/jdk1.5/lib:."
declare -x COLORTERM="gnome-terminal"
declare -x CROSS_COMPILE="arm-eabi-"
declare -x DBUS_SESSION_BUS_ADDRESS="unix:abstract=/tmp/dbus-OJvpLZd03U,guid=d94147f73fa475274a61cf044b397f7f"
declare -x DESKTOP_SESSION="default"
declare -x DISPLAY=":0.0"
declare -x GDMSESSION="default"
declare -x GDM_LANG="zh_CN.UTF-8"
declare -x GDM_XSERVER_LOCATION="local"
declare -x GNOME_DESKTOP_SESSION_ID="this-is-deprecated"
declare -x GNOME_KEYRING_PID="5034"
declare -x GNOME_KEYRING_SOCKET="/tmp/keyring-YFVFeN/socket"
declare -x GPG_AGENT_INFO="/tmp/seahorse-Wf9VIW/S.gpg-agent:5156:1"
declare -x GTK_IM_MODULE="scim-bridge"
declare -x GTK_RC_FILES="/etc/gtk/gtkrc:/root/.gtkrc-1.2-gnome2"
declare -x HOME="/root"
declare -x JAVA_HOME="/usr/local/jdk1.5"
declare -x LANG="zh_CN.UTF-8"
declare -x LESSCLOSE="/usr/bin/lesspipe %s %s"
declare -x LESSOPEN="| /usr/bin/lesspipe %s"
declare -x LOGNAME="root"
declare -x LS_COLORS="no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:su=37;41:sg=30;43:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.svgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.lzma=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.rar=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*.tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf=01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.mid=00;36:*.midi=00;36:*.mka=00;36:*.mp3=00;36:*.mpc=00;36:*.ogg=00;36:*.ra=00;36:*.wav=00;36:"
declare -x OLDPWD="/home/wolfrun"
declare -x ORBIT_SOCKETDIR="/tmp/orbit-root"
declare -x PATH="/opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:::"
declare -x PWD="/home"
declare -x QT_IM_MODULE="xim"
declare -x SESSION_MANAGER="local/wolfrun-desktop:/tmp/.ICE-unix/5044"
declare -x SHELL="/bin/bash"
declare -x SHLVL="1"
declare -x SSH_AUTH_SOCK="/tmp/keyring-YFVFeN/ssh"
declare -x TERM="xterm"
declare -x USER="root"
declare -x USERNAME="root"
declare -x WINDOWID="35662851"
declare -x WINDOWPATH="7"
declare -x XAUTHORITY="/root/.Xauthority"
declare -x XDG_DATA_DIRS="/usr/local/share/:/usr/share/:/usr/share/gdm/"
declare -x XDG_SESSION_COOKIE="25406e5978e6d7d6afd6e9044af03730-1262059389.778017-1900349992"
declare -x XMODIFIERS="@im=SCIM"

 

(2) echo $ENV_NAME                     /* 檢視ENV_NAME的環境變數*/

 

[示例]:

root@wolfrun-desktop: /home# echo $PATH

/opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:::

 

 

 

2. 設定環境變數

 

(1) export ENV_NAME=ENV_VALUE:$ENV_NAME      /* 臨時設定ENV_NAME的環境變數,重啟開機後丟失 */

 

[示例]:

root@wolfrun-desktop: /home#export  PATH=/usr/local/arm-linux/bin:$PATH

root@wolfrun-desktop: /home#echo $PATH

/usr/local/arm-linux/bin:/opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:::

 

root@wolfrun-desktop: /home#export  PATH=$PATH:/usr/local/arm-linux/bin:

root@wolfrun-desktop: /home#echo $PATH

opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/arm-linux/bin:::

 

(2) echo "                                                                  /* 永久設定ENV_NAME的環境變數,重啟開機後存在 */

     ENV_NAME=ENV_VALUE:/$ENV_NAME:

     export PATH

     " >>/etc/bash.bashrc

 

[示例]:

root@wolfrun-desktop: /home#echo "                                                                 

>   PATH=/usr/local/arm-linux/bin:/$PATH:

>   export PATH

>   " >>/etc/bash.bashrc

root@wolfrun-desktop: /home#echo $PATH

/usr/local/arm-linux/bin:/opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:::

 

 

(3) vim /etc/bash.bashrc                                           /* 永久設定ENV_NAME的環境變數,重啟開機後存在 */

      增加 ENV_NAME=ENV_VALUE:$ENV_NAME

             export ENV_NAME

 

[示例]:

root@wolfrun-desktop: /home#vim /etc/bash.bashrc

增加:

PATH=/usr/local/arm-linux/bin:$PATH

export PATH

 

root@wolfrun-desktop: /home#echo $PATH

/usr/local/arm-linux/bin:/opt/arm-eabi/bin:/usr/local/jdk1.5/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:::

 

 

 

3. 刪除環境變數

 

(1) unset ENV_NAME                                                 /* 刪除環境變數 */

 

[示例]:

root@wolfrun-desktop: /home#echo $TESTPATH

/home

root@wolfrun-desktop: /home#unset TESTPATH

 

 

 

註明:  ( 驗證環境  -  wolfrun@Ubuntu 8.10-desktop )