Appendix H. Important System Directories
Sysadmins and anyone else writing administrative scripts should be intimately familiar with the following system directories.
/bin Binaries (executables). Basic system programs and utilities (such as bash).
/usr/bin [1]More system binaries.
/usr/local/bin Miscellaneous binaries local to the particular machine.
/sbin System binaries. Basic system administrative programs and utilities (such as fsck).
/usr/sbin More system administrative programs and utilities.
/etc Et cetera. Systemwide configuration scripts.
Of particular interest are the
/etc/fstab (filesystem table),/etc/mtab (mounted filesystem table), and the/etc/inittab files./etc/rc.d Boot scripts, on Red Hat and derivative distributions of Linux.
/usr/share/doc Documentation for installed packages.
/usr/man The systemwide manpages.
/dev Device directory. Entries (but not mount points) for physical and virtual devices. See Chapter 27.
/proc Process directory. Contains information and statistics about running processes and kernel parameters. See Chapter 27.
/sys Systemwide device directory. Contains information and statistics about device and device names. This is newly added to Linux with the 2.6.X kernels.
/mnt Mount. Directory for mounting hard drive partitions, such as
/mnt/dos , and physical devices. In newer Linux distros, the/media directory has taken over as the preferred mount point for I/O devices./media In newer Linux distros, the preferred mount point for I/O devices, such as CD/DVD drives or USB flash drives.
/var Variable (changeable) system files. This is a catchall "scratchpad" directory for data generated while a Linux/UNIX machine is running.
/var/log Systemwide log files.
/var/spool/mail User mail spool.
/lib Systemwide library files.
/usr/lib More systemwide library files.
/tmp System temporary files.
/boot System boot directory. The kernel, module links, system map, and boot manager reside here.
Altering files in this directory may result in an unbootable system.