How to use the Linux export command

When executing a program in a shell, the shell provides a set of environment variables. Export can add, modify, or delete environment variables for use by subsequent programs. The effect of export only extends to the landing operation.

Grammar

Export [-fnp][variable name]=[variable set value]

Parameter description:

• -F represents the function name in the variable name.
• -n Deletes the specified variable. Variables are not actually deleted, but are not exported to the execution environment of subsequent directives.
• -p lists all the environment variables that the shell assigns to the program.

Instance

List all current environment variables

# export-p//list Current environment variable values

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"

Defining environment variables

# Export MYENV//define environment variables

# export-p//list Current environment variables

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"

Define environment variable Assignment

# Export MYENV=7//Define environment variables and assign values

# 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"