create a new environment variable in linux [openwrt]

Question

I want to use environment variable to save value and after reboot the system, this variable must contain the last value saved
I try this

root@OpenWrt:~# BOOTT=1
root@OpenWrt:~# export
export HOME='/root'
export LOGNAME='root'
export PATH='/bin:/sbin:/usr/bin:/usr/sbin'
export PS1='\u@\h:\w\$ '
export PWD='/root'
export SHELL='/bin/ash'
export SSH_CONNECTION='192.168.1.110 2961 192.168.1.122 22'
export SSH_TTY='/dev/pts/0'
export TERM='xterm'
export USER='root'
root@OpenWrt:~# export BOOTT
root@OpenWrt:~# export
export BOOTT='1'
export HOME='/root'
export LOGNAME='root'
export PATH='/bin:/sbin:/usr/bin:/usr/sbin'
export PS1='\u@\h:\w\$ '
export PWD='/root'
export SHELL='/bin/ash'
export SSH_CONNECTION='192.168.1.110 2961 192.168.1.122 22'
export SSH_TTY='/dev/pts/0'
export TERM='xterm'
export USER='root'
root@OpenWrt:~#
root@OpenWrt:~# reboot
root@OpenWrt:~#

==> after reboot

root@OpenWrt:~# export
export HOME='/root'
export LOGNAME='root'
export PATH='/bin:/sbin:/usr/bin:/usr/sbin'
export PS1='\u@\h:\w\$ '
export PWD='/root'
export SHELL='/bin/ash'
export SSH_CONNECTION='192.168.1.110 3217 192.168.1.122 22'
export SSH_TTY='/dev/pts/0'
export TERM='xterm'
export USER='root'
root@OpenWrt:~# echo $BOOTT
root@OpenWrt:~#

so can I obtain env variable which can saved value after reboot !!

Answer 1

Add the following to your $HOME/.profile:

BOOTT=1
export BOOTT

Answer 2

Or if you want to make those variables globally, put them in /etc/profile and source this file in .bashrc of each user.