Specific Options
The following programs, or symbolic links to programs, must be in /bin if the corresponding subsystem is installed:
| Command | Description |
|---|---|
| csh | The C shell (optional) |
| ed | The `ed' editor (optional) |
| tar | The tar archiving utility (optional) |
| cpio | The cpio archiving utility (optional) |
| gzip | The GNU compression utility (optional) |
| gunzip | The GNU uncompression utility (optional) |
| zcat | The GNU uncompression utility (optional) |
| netstat | The network statistics utility (optional) |
| ping | The ICMP network test utility (optional) |
If the gunzip and zcat programs exist, they must be symbolic or hard links to gzip. /bin/csh may be a symbolic link to /bin/tcsh or /usr/bin/tcsh.
The tar, gzip and cpio commands have been added to make restoration of a system possible (provided that / is intact).
Conversely, if no restoration from the root partition is ever expected, then these binaries might be omitted (e.g., a ROM chip root, mounting /usr through NFS). If restoration of a system is planned through the network, then ftp or tftp (along with everything necessary to get an ftp connection) must be available on the root partition.