==== simple_vars ====
user@host ~ $ X=5
user@host ~ $ Y=text
user@host ~ $ Z="Mary had a little lamb"
user@host ~ $ echo $Z $Y$X.txt
Mary had a little lamb text5.txt
user@host ~ $ E=echo
user@host ~ $ $E $Z > $Y$X.txt
user@host ~ $ cat text5.txt
Mary had a little lamb
user@host ~ $ export W=word
user@host ~ $ export Y
user@host ~ $ echo "W='$W' X='$X' Y='$Y' Z='$Z'"
W='word' X='5' Y='text' Z='Mary had a little lamb'
user@host ~ $ sh
sh-5.1$ echo "W='$W' X='$X' Y='$Y' Z='$Z'"
W='word' X='' Y='text' Z=''
sh-5.1$ Y="another_text"
sh-5.1$ echo "W='$W' X='$X' Y='$Y' Z='$Z'"
W='word' X='' Y='another_text' Z=''
sh-5.1$ exit
exit
user@host ~ $ echo "W='$W' X='$X' Y='$Y' Z='$Z'"
W='word' X='5' Y='text' Z='Mary had a little lamb'
~~META: language = en ~~