This section contains information related to system operation and maintenance. It describes commands used to create new file systems, newfs(8), verify the integrity of the file systems, fsck(8), control disk usage, edquota(8), maintain system backups, dump(8), and recover files when disks die an untimely death, restore(8). Network related services like inetd(8) and ftpd(8) are also described. The crash(8) manual page should be consulted to understand how to interpret system crash dumps.
All commands set an exit status. Its value may be tested to see if the command completed normally. Unless otherwise noted (rare), the value 0 signifies successful completion of the command, while a value >0 indicates an error. Some commands attempt to describe the nature of the failure by using error codes defined in sysexits(3), or set the status to arbitrary values >0 (typically 1), but many such values are not described in the manual.
The intro section manual page appeared in BSD 4.2 .