I'm trying to understand something about environment variables, and I checked through some common ones listed in an LPIC exam guide. It talks about HISTSIZE among other HIST variables, but it says that HISTSIZE and things like HISTCONTROL are common environment variables. However my testing is inconclusive. In my test below, i check if HISTSIZE is a global environment variable, but it's not. But when I echo it, I see a result, so my assumption is that its a local/shell variable. However, I spawn a new bash child-shell and the value is still there, so it must be a global/environment variable. So how is it not int he result of printenv or export?
$ printenv HISTSIZE $ export | grep HISTSIZE $ echo $HISTSIZE 1000 $ bash $ echo $HISTSIZE 1000