The following commands, or symbolic links to commands, are required in /bin.
| cat | Utility to concatenate files to standard output |
| chgrp | Utility to change file group ownership |
| chmod | Utility to change file access permissions |
| chown | Utility to change file owner and group |
| cp | Utility to copy files and directories |
| date | Utility to print or set the system data and time |
| dd | Utility to convert and copy a file |
| df | Utility to report filesystem disk space usage |
| dmesg | Utility to print or control the kernel message buffer |
| echo | Utility to display a line of text |
| false | Utility to do nothing, unsuccessfully |
| hostname | Utility to show or set the system's host name |
| kill | Utility to send signals to processes |
| ln | Utility to make links between files |
| login | Utility to begin a session on the system |
| ls | Utility to list directory contents |
| mkdir | Utility to make directories |
| mknod | Utility to make block or character special files |
| more | Utility to page through text |
| mount | Utility to mount a filesystem |
| mv | Utility to move/rename files |
| ps | Utility to report process status |
| pwd | Utility to print name of current working directory |
| rm | Utility to remove files or directories |
| rmdir | Utility to remove empty directories |
| sed | The `sed' stream editor |
| sh | The Bourne command shell |
| stty | Utility to change and print terminal line settings |
| su | Utility to change user ID |
| sync | Utility to flush filesystem buffers |
| true | Utility to do nothing, successfully |
| umount | Utility to unmount file systems |
| uname | Utility to print system information |
Table 3.4.2.1
If /bin/sh is not a true Bourne shell, it must be a hard or symbolic link to the real shell command.
The [ and test commands must be placed together in either /bin or /usr/bin.
The requirement for the [ and test commands to be
included as binaries (even if implemented internally by the shell) is shared with the POSIX.2 standard.
| 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) |
Table 3.4.3.2
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.
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.
[1] Command binaries that are not essential enough to place into /bin must be placed in /usr/bin, instead. Items that are required only by non-root users (the X Window System, chsh, etc.) are generally not essential enough to be placed into the root partition.