Random envionment variables

CrazyCatLover · 11-08-2014, 10:11 PM

Hi,
1.typing env shows the environment variables
2.$RANDOM is an environment varible
So why doesnt typing env shows the $RANDOM environment varible?

273 · 11-08-2014, 10:17 PM

Because it's not an environmental variable?

rtmistler · 11-10-2014, 12:11 PM

$RANDOM is special. You can echo it but it's not part of the environment:

Code:

$ echo $RANDOM
32408
$ env | grep RANDOM
$

Soderlund · 11-10-2014, 01:17 PM

$RANDOM is also not present in the old Heirloom shell. Bash, pdksh and probably most other modern shells have it. The other way of getting a random number is (for example):

Code:

hexdump -n 1 -e '/1 "%u"' /dev/urandom