# sysctl > List and change kernel runtime variables. > More information: . - Show all available variables and their values: `sysctl {{[-a|--all]}}` - Set a changeable kernel state variable: `sysctl {{[-w|--write]}} {{section.tunable}}={{value}}` - Get currently open file handlers: `sysctl fs.file-nr` - Get limit for simultaneous open files: `sysctl fs.file-max` - Apply changes from `/etc/sysctl.conf`: `sysctl {{[-p|--load]}}`