Linux—export命令

Linux export命令用于设置或显示环境变量。

在shell中执行程序时,shell会提供一组环境变量。export可新增,修改或删除环境变量,供后续执行的程序使用。export的效力仅及于该次登陆操作。

语法

export [-fnp][变量名称]=[变量设置值]

参数说明

  • -f  代表[变量名称]中为函数名称。
  • -n  删除指定的变量。变量实际上并未删除,只是不会输出到后续指令的执行环境中。
  • -p  列出所有的shell赋予程序的环境变量。

实例

列出当前所有的环境变量

# export -p //列出当前的环境变量值
declare -x HOME=“/root
declare -x LANG=“zh_CN.UTF-8
declare -x LANGUAGE=“zh_CN:zh
declare -x LESSCLOSE=“/usr/bin/lesspipe %s %s
declare -x LESSOPEN=“| /usr/bin/lesspipe %s
declare -x LOGNAME=“root
declare -x LS_COLORS=““
declare -x MAIL=“/var/mail/root
declare -x OLDPWD
declare -x PATH=“/opt/toolchains/arm920t-eabi/bin:/opt/toolchains/arm920t-eabi/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
declare -x PWD=“/root
declare -x SHELL=“/bin/bash
declare -x SHLVL=“1
declare -x SPEECHD_PORT=“6560
declare -x SSH_CLIENT=“192.168.1.65 1674 22
declare -x SSH_CONNECTION=“192.168.1.65 1674 192.168.1.3 22
declare -x SSH_TTY=“/dev/pts/2
declare -x TERM=“XTERM
declare -x USER=“root
declare -x XDG_SESSION_COOKIE=“93b5d3d03e032c0cf892a4474bebda9f-1273864738.954257-340206484

定义环境变量

# export MYENV //定义环境变量
# export -p //列出当前的环境变量
declare -x HOME=“/root
declare -x LANG=“zh_CN.UTF-8
declare -x LANGUAGE=“zh_CN:zh
declare -x LESSCLOSE=“/usr/bin/lesspipe %s %s
declare -x LESSOPEN=“| /usr/bin/lesspipe %s
declare -x LOGNAME=“root
declare -x LS_COLORS=““
declare -x MAIL=“/var/mail/root
declare -x MYENV
declare -x OLDPWD
declare -x PATH=“/opt/toolchains/arm920t-eabi/bin:/opt/toolchains/arm920t-eabi/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
declare -x PWD=“/root
declare -x SHELL=“/bin/bash
declare -x SHLVL=“1
declare -x SPEECHD_PORT=“6560
declare -x SSH_CLIENT=“192.168.1.65 1674 22
declare -x SSH_CONNECTION=“192.168.1.65 1674 192.168.1.3 22
declare -x SSH_TTY=“/dev/pts/2
declare -x TERM=“XTERM
declare -x USER=“root
declare -x XDG_SESSION_COOKIE=“93b5d3d03e032c0cf892a4474bebda9f-1273864738.954257-340206484

定义环境变量赋值

# export MYENV=7 //定义环境变量并赋值
# export -p
declare -x HOME=“/root
declare -x LANG=“zh_CN.UTF-8
declare -x LANGUAGE=“zh_CN:zh
declare -x LESSCLOSE=“/usr/bin/lesspipe %s %s
declare -x LESSOPEN=“| /usr/bin/lesspipe %s
declare -x LOGNAME=“root
declare -x LS_COLORS=““
declare -x MAIL=“/var/mail/root
declare -x MYENV=“7
declare -x OLDPWD
declare -x PATH=“/opt/toolchains/arm920t-eabi/bin:/opt/toolchains/arm920t-eabi/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games
declare -x PWD=“/root
declare -x SHELL=“/bin/bash
declare -x SHLVL=“1
declare -x SPEECHD_PORT=“6560
declare -x SSH_CLIENT=“192.168.1.65 1674 22
declare -x SSH_CONNECTION=“192.168.1.65 1674 192.168.1.3 22
declare -x SSH_TTY=“/dev/pts/2
declare -x TERM=“XTERM
declare -x USER=“root
declare -x XDG_SESSION_COOKIE=“93b5d3d03e032c0cf892a4474bebda9f-1273864738.954257-340206484
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