chapter: Important Files (part 2)

Author: pmarinov

pages/important_files.poly.pm

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+#lang pollen
+
+◊page-init{}
+◊define-meta[page-title]{Important Files}
+◊define-meta[page-description]{Important Files and Folders}
+
+◊section{Important Files}
+
+◊definition-block[#:type "code"]{
+
+◊definition-entry[#:name "/etc/profile"]{
+Systemwide defaults, mostly setting the environment (all Bourne-type
+shells, not just Bash ◊footnote{This does not apply to ◊command{csh},
+◊command{tcsh}, and other shells not related to or descended from the
+classic Bourne shell (◊command{sh}).})
+
+}
+
+◊definition-entry[#:name "/etc/bashrc"]{
+Systemwide functions and aliases for Bash
+
+}
+
+◊definition-entry[#:name "$HOME/.bash_profile"]{
+User-specific Bash environmental default settings, found in each
+user's home directory (the local counterpart to ◊fname{/etc/profile})
+
+}
+
+◊definition-entry[#:name "$HOME/.bashrc"]{
+User-specific Bash init file, found in each user's home directory (the
+local counterpart to ◊fname{/etc/bashrc}). Only interactive shells and
+user scripts read this file. See TODO Appendix M for a sample
+◊fname{.bashrc} file.
+
+}
+
+◊definition-entry[#:name "$HOME/.bash_logout"]{
+User-specific instruction file, found in each user's home
+directory. Upon exit from a login (Bash) shell, the commands in this
+file execute.
+
+}
+
+◊definition-entry[#:name "/etc/passwd"]{
+A listing of all the user accounts on the system, their identities,
+their home directories, the groups they belong to, and their default
+shell. Note that the user passwords are not stored in this file, but
+in ◊fname{/etc/shadow} in encrypted form. ◊footnote{In older versions
+of UNIX, passwords were stored in ◊fname{/etc/passwd}, and that
+explains the name of the file.}
+
+}
+
+◊definition-entry[#:name "/etc/sysconfig/hwconf"]{
+Listing and description of attached hardware devices. This information
+is in text form and can be extracted and parsed.
+
+◊example{
+bash$ grep -A 5 AUDIO /etc/sysconfig/hwconf	      
+class: AUDIO
+bus: PCI
+detached: 0
+driver: snd-intel8x0
+desc: "Intel Corporation 82801CA/CAM AC'97 Audio Controller"
+vendorId: 8086
+}
+
+Note: This file is present on Red Hat and Fedora Core installations,
+but may be missing from other distros.
+
+}
+
+}
+
+◊section{Important System Directories}
+
+Sysadmins and anyone else writing administrative scripts should be
+intimately familiar with the following system directories.
+
+◊definition-block[#:type "code"]{
+
+◊definition-entry[#:name "/bin"]{
+Binaries (executables). Basic system programs and utilities (such as
+◊command{bash}).
+
+}
+
+◊definition-entry[#:name "/usr/bin"]{
+More system binaries. ◊footnote{Some early UNIX systems had a fast,
+small-capacity fixed disk (containing ◊fname{/}, the root partition), and a
+second drive which was larger, but slower (containing ◊fname{/usr} and other
+partitions). The most frequently used programs and utilities therefore
+resided on the small-but-fast drive, in ◊fname{/bin}, and the others on the
+slower drive, in ◊fname{/usr/bin}.
+
+This likewise accounts for the split between ◊fname{/sbin} and
+◊fname{/usr/sbin}, ◊fname{/lib} and ◊fname{/usr/lib}, etc.}
+
+}
+
+◊definition-entry[#:name "/usr/local/bin"]{
+Miscellaneous binaries local to the particular machine.
+
+}
+
+◊definition-entry[#:name "/sbin"]{
+System binaries. Basic system administrative programs and utilities
+(such as ◊command{fsck}).
+
+}
+
+◊definition-entry[#:name "/etc"]{
+Et cetera. Systemwide configuration scripts.
+
+Of particular interest are the ◊fname{/etc/fstab} (filesystem table),
+◊fname{/etc/mtab} (mounted filesystem table), and the
+◊fname{/etc/inittab} files.
+
+}
+
+◊definition-entry[#:name "/etc/rc.d"]{
+Boot scripts, on Red Hat and derivative distributions of Linux.
+
+}
+
+◊definition-entry[#:name "/usr/share/doc"]{
+Documentation for installed packages.
+
+}
+
+◊definition-entry[#:name "/usr/man"]{
+The systemwide manpages.
+
+}
+
+◊definition-entry[#:name "/dev"]{
+Device directory. Entries (but not mount points) for physical and
+virtual devices. See TODO Chapter 29.
+
+}
+
+◊definition-entry[#:name "/proc"]{
+Process directory. Contains information and statistics about running
+processes and kernel parameters. See TODO Chapter 29.
+
+}
+
+◊definition-entry[#:name "/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.
+
+}
+
+◊definition-entry[#:name "/mnt"]{
+Mount.
+
+Directory for mounting hard drive partitions, such as
+◊fname{/mnt/dos}, and physical devices. In newer Linux distros, the
+◊fname{/media} directory has taken over as the preferred mount point
+for I/O devices.
+
+}
+
+◊definition-entry[#:name "/media"]{
+In newer Linux distros, the preferred mount point for I/O devices,
+such as CD/DVD drives or USB flash drives.
+
+}
+
+◊definition-entry[#:name "/var"]{
+Variable (changeable) system files.
+
+This is a catchall "scratchpad" directory for data generated while a
+Linux/UNIX machine is running.
+
+}
+
+◊definition-entry[#:name "/var/log"]{
+Systemwide log files.
+
+}
+
+◊definition-entry[#:name "/var/spool/mail"]{
+User mail spool.
+
+}
+
+◊definition-entry[#:name "/lib"]{
+Systemwide library files.
+
+}
+
+◊definition-entry[#:name "/usr/lib"]{
+More systemwide library files.
+
+}
+
+◊definition-entry[#:name "/tmp"]{
+System temporary files. All files here are deleted at boot time.
+
+}
+
+◊definition-entry[#:name "/boot"]{
+System boot directory.
+
+The kernel, module links, system map, and boot manager reside here.
+
+Warning: Altering files in this directory may result in an unbootable
+system.
+
+}
+
+}