BASH_VERSION is empty even though SHELL is /bin/bash

Question

I have run into an issue when executing script in /etc/profile.d/script.sh. On one of my machines (only this one, on the others it is running well), when I do

echo "$BASH_VERSION" >> /home/synek317/log
echo "$SHELL"        >> /home/synek317/log

the result is that BASH_VERSION is empty, but SHELL is /bin/bash. However, when I run terminal and type echo $BASH_VERSION, it is filled correctly.

I run this on Ubuntu 16.04.1.

Do you have any ideas why is this variable empty during execution of /etc/profile.d/ scripts?

this is fresh copy of ubuntu. It is empty only during login. — synek317
– synek317, Commented Oct 3, 2016 at 16:08
The only place I found is /usr/sbin/lightdm-session but it is the same on other machine... — synek317
– synek317, Commented Oct 3, 2016 at 16:24
SHELL is not necessarily the name of the current shell; it's the name of your login shell. The scripts in /etc/profile.d may be executed by /bin/sh, which is dash in Ubuntu. — chepner
– chepner, Commented Oct 3, 2016 at 16:30
Write env, set, $$, pwd, id, "ps -aef" and all such other things in to the file along with BASH_VERSION and SHELL. That should give you clues on what shell executed it and what was its environment like. — blackpen
– blackpen, Commented Oct 3, 2016 at 16:53
Thanks for the clues. I have found out that all of this is working, well, accidentally. The line in my profile.d script checks not empty BASH_VERSION or ZSH_VERSION. lightdm-session sets BASH_VERSION as empty var when launching profile scripts. So it means that my profile.d script works only because of ZSH_VERSION is set. Now the question is why on one machine it is set and on the other it is not. It is weird however. — synek317
– synek317, Commented Oct 3, 2016 at 17:06

tripleee · Accepted Answer · 2016-10-04 01:33:02Z

1

By definition, /etc/profile.d scripts are not run by Bash.

answered Oct 4, 2016 at 1:33

tripleee

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1 Comment

ARX Over a year ago

This answer is correct, but may leave you wondering who reads those scripts. See unix.stackexchange.com/questions/462663/…

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