>Usage
The export command in Unix is used to set environment variables, making them available to child processes spawned from the current shell session.
When you define a variable in a shell, it is by default local to the shell session. This means the variable is not accessible to any child processes or other shells. However, by using export, you make the variable available to any processes or programs launched from the current shell.
>Synopsis
>Options
VAR=value
The command VAR=value sets a new environment
variable and exports it so that it is available to all child
processes.
It both assigns the variable and makes it available to any
processes spawned from the current shell session.
Example:
-zsh
> export MY_VAR="Hello, World!"
No output;
The variable is set and exported silently. You can verify it
by checking with echo or env:
> echo $MY_VAR
> Hello, World!
-p
The command -p displays all currently exported variables in the shell environment. When you run export -p, you’ll see a list of variables that have been marked for export, along with their values
Example:
-zsh
> export -p
declare -x HOME="/home/user"
declare -x
LANG="en_US.UTF-8"
declare -x MY_VAR="Hello, World!"
declare -x
PATH="/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin"
VAR+=value
The command VAR+=value is used to append a new value to an existing variable. This allows you to add more content to an environment variable or shell variable without overwriting its current value.
Example:
-zsh
> VAR="Hello"
> VAR+=" World"
> echo $VAR
Hello World
-f
The command -f command is used to export a function to child processes in a shell. When you define a function in a shell, by default that function is only available in the current shell session. However, if you want that function to be available to any child processes that are spawned from the current shell, you need to export the function using export -f.
Example:
-zsh
> export -f function_name
No output will be shown when you run export -f.