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I am trying to set an environment variable in linux. This is the script Ive come up with:

import time
import board
import os
from adafruit_htu21d import HTU21D

i2c = board.I2C()
sensor = HTU21D(i2c)
refresh_rate = 1
if __name__ == "__main__":
        while True:
                os.environ["AMBIENT_TEMPC"] = str(sensor.temperature)
                os.environ["AMBIENT_TEMPF"] = (sensor.temperature * 9 / 5) + 32
                os.environ["AMBIENT_HUMID"] = sensor.relative_humidity
                time.sleep(refresh_rate)

This script just continues to run in the background, meant to update the environment variables. The problem is that I don't see these variables anywhere when I try to access them from within bash. env and export return essentially the same results, which exclude the variables that should have been added\updated.

SHELL=/bin/bash
NO_AT_BRIDGE=1
PWD=/home/pi/Projects/octo_temp
LOGNAME=pi
XDG_SESSION_TYPE=tty
HOME=/home/pi
LANG=en_US.UTF-8
LS_COLORS=rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz=01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.zst=01;31:*.tzst=01;31:*.bz2=01;31:*.bz=01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;31:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.wim=01;31:*.swm=01;31:*.dwm=01;31:*.esd=01;31:*.jpg=01;35:*.jpeg=01;35:*.mjpg=01;35:*.mjpeg=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:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mpeg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=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:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35:*.emf=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=00;36:*.au=00;36:*.flac=00;36:*.m4a=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:*.oga=00;36:*.opus=00;36:*.spx=00;36:*.xspf=00;36:
VIRTUAL_ENV=/home/pi/oprint
SSH_CONNECTION=fe80::bd38:440:1d3b:90ed%wlan0 58780 fe80::977c:ef7a:d7d9:cf04%wlan0 22
XDG_SESSION_CLASS=user
TERM=xterm
USER=pi
SHLVL=1
XDG_SESSION_ID=3
XDG_RUNTIME_DIR=/run/user/1000
PS1=(oprint) \[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w \$\[\033[00m\]
SSH_CLIENT=fe80::bd38:440:1d3b:90ed%wlan0 58780 22
PATH=/home/pi/oprint/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/local/games:/usr/games
MAIL=/var/mail/pi
SSH_TTY=/dev/pts/1
TEXTDOMAIN=Linux-PAM
_=/usr/bin/env
OLDPWD=/home/pi/Projects

What am I missing here?

addohm
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    At least in Unix-like OSes, environment variables are local to each process (except that subprocesses inherit a copy of the parent process's environment, as of when they were forked). That means you're setting env variables in the Python process, but these have no effect outside that process. – Gordon Davisson Aug 18 '21 at 23:29

0 Answers0