Make variables lower-case

In order not to have conflicts with the system’s environment variables,
custom variables are conventionally set in lower case.

random-password

@@ -1,3 +1,3 @@
 #!/bin/bash
-LENGTH=${1:-32}
-cat /dev/urandom | tr -dc 'a-zA-Z0-9-_!@#$%^&*()_+{}|:<>?=' | fold -w $LENGTH | head -n 1 | grep -i '[!@#$%^&*()_+{}|:<>?=]'
+length=${1:-32}
+cat /dev/urandom | tr -dc 'a-zA-Z0-9-_!@#$%^&*()_+{}|:<>?=' | fold -w $length | head -n 1 | grep -i '[!@#$%^&*()_+{}|:<>?=]'