selinuxenabled: add page (#18444)

Author: pranlawate

pages/linux/selinuxenabled.md

@@ -0,0 +1,18 @@
+# selinuxenabled
+
+> Check whether SELinux is enabled.
+> Returns exit code 0 if SELinux is enabled, and 1 if it is not.
+> See also: `getenforce`, `setenforce`, `sestatus`.
+> More information: <https://manned.org/selinuxenabled>.
+
+- Check if SELinux is enabled (no output; check exit code with `echo $?`):
+
+`selinuxenabled`
+
+- Check if SELinux is enabled and print the result:
+
+`selinuxenabled && echo "SELinux is enabled" || echo "SELinux is disabled"`
+
+- Use in a shell script to conditionally execute commands:
+
+`if selinuxenabled; then echo "SELinux is running"; fi`