Locations - Reverse Flashcards
~/.bash_history
the bash history
/usr/lib/rpm/rpmrc
typically you don’t edit this file
rpm main configuration file
/etc/rpmrc
create it if it doesn’t exist
The main reason to create such a file is to implement architecture optimizations—for instance; to optimize your code for your CPU model by passing appropriate compiler options when you build a source RPM into a binary RPM. This is done with the optflags line:
optflags: athlon -O2 -g -march=i686
rpm global configuration file for editing
∼ /.rpmrc
create it if it doesn’t exist
The main reason to create such a file is to implement architecture optimizations—for instance; to optimize your code for your CPU model by passing appropriate compiler options when you build a source RPM into a binary RPM. This is done with the optflags line:
optflags: athlon -O2 -g -march=i686
rpm per user configuration file for editing
/etc/yum.conf
holds basic options; such as the directory to which Yum downloads RPMs and where Yum logs its activities. Chances are that you won’t need to modify this file
yum configuration file
/etc/yum.repos.d/
You probably shouldn’t directly edit these files; instead; if you want to add a repository; you should manually download the RPM that includes the repository configuration and install it using rpm . The next time you use Yum; it will access your new repository along with the old ones
yum additional configuration files
/etc/apt/sources.list
okay to modify
apt repository configuration
/etc/dpkg/dpkg.cfg or ∼/.dpkg.cfg
The main configuration file for dpkg
/etc/apt/apt.conf
BIND formatting
controls apt and dselect options
/var/lib/dpkg
the debian installed file database
/etc/ld.so.conf
Generally speaking; there’s seldom a need to change the library path system wide
library path
/lib and /usr/lib
These directories are always on the library path; even if they aren’t listed in ld.so.conf .
trusted library directories
/etc/ld.so.cache
shared library cache
/proc/interrupts
virtual filesystem
only shows an entry after a driver that uses the interrupt is loaded
interrupts
/dev/ttyS0
Windows name COM1, IRQ 4
/dev/ttyS1
Windows name COM2; IRQ 3
/dev/ttyS2
Windows name COM3; IRQ 4
/dev/ttyS3
Windows name COM4; IRQ 3
/dev/lp0
Windows name LPT1; IRQ 7
/dev/lp1
Windows name LPT2; IRQ 5
/dev/fd0
Windows name A:; IRQ 6
/dev/fd1
Windows name B:; IRQ 6
/proc/ioports
what I/O addresses the computer is using
/proc/dma
what DMA channels your system uses
/sys
sysfs virtual filesystem, contains information about devices so that user-space utilities can access the information
/dev
a place where dynamic device files as drivers are loaded and unloaded; necessitated by hotplug devices
/lib/modules
kernel module files; kernel drivers for hardware
/proc/modules
currently loaded kernel modules
/etc/modprobe.conf
or
/etc/modprobe.d/
modprobe configuration
/proc/bus/usb
connected usb devices
/dev/mapper
where logical volumes for LVM are mapped to names
swap partition (mounted with swapon to /swap)
Serves as an adjunct to system RAM. It is slow but enables the computer to run more or larger programs.
/home partition
Holds users’ data files. Isolating it on a separate partition preserves user data during a system upgrade. Size depends on the number of users and their data storage needs.
/boot partition
Holds critical boot files. Creating it as a separate partition lets you circumvent limitations of older BIOSs and boot loaders; which often can’t boot a kernel from a point above a value between 504MiB and 2TiB.
/usr partition
Holds most Linux program and data files; this is sometimes the largest partition; although /home is larger on systems with many users or if users store large data files. Changes implemented in 2012 are making it harder to create a separate /usr partition in many distributions
/usr/local partition
Holds Linux program and data files that are unique to this installation; particularly those that you compile yourself
/opt partition
Holds Linux program and data files that are associated with third- party packages; especially commercial ones
/var partition
Holds miscellaneous files associated with the day-to-day functioning of a computer. These files are often transient in nature. Most often split off as a separate partition when the system functions as a server that uses the /var directory for server-related files like mail queues.
/tmp partition
Holds temporary files created by ordinary users.
/mnt partition
Not a separate partition; rather; it or its subdirectories are used as mount points for removable media like CDs and DVDs.
/media partition
Holds subdirectories that may be used as mount points for removable media; much like /mnt or its subdirectories.
/etc/fstab
the partitions that are mounted on boot and their mount points
/etc/mtab
a list of filesystems linux has mounted; don’t edit it
/
root directory
/boot
contains static and unshareable files related to the computer’s initial booting. Higher-level startup and configuration files reside in another directory; /etc . In this directory; you will find GRUB or LILO configuration files along with the other files necessary for the initial boot. typically; it is recommended that you store /boot on its own partition.
/etc
contains unshareable and static system configuration files. These higher-level startup and configuration files control the various programs and services offered on a system
If the Linux distribution uses SysV system initialization; its configuration files are stored here
/bin
contains certain critical executable files; such as ls ; cp ; and mount . These commands are accessible to all users and constitute the most important commands that ordinary users might issue
static files; almost never shared
/sbin
similar to /bin ; but it contains programs that are normally run only by the system administrator—tools like fdisk and e2fsck . It’s static and theoretically shareable; but in practice it makes no sense to share it
/lib
similar to /bin and /sbin ; but it contains program libraries. Program libraries consist of code that’s shared across many programs and stored in separate files to save disk space and RAM.
is static and theoretically shareable; although it’s not shared in practice
/usr
hosts the bulk of a Linux computer’s programs. Its contents are shareable and static; so it can be mounted read-only and may be shared with other Linux systems. For these reasons; many administrators split /usr off into a separate partition; although doing so isn’t required
/usr/local
mirror the organization of /usr
osts files that a system administrator installs locally—for instance; packages that are compiled on the target computer. The idea is to have an area that’s safe from automatic software upgrades when the OS as a whole is upgraded.
Some system administrators split this off into its own partition to protect it from OS reinstallation procedures that might erase the parent partition.
/usr/share/man
stores the manual pages used by the man command
/usr/X11R6
houses files related to the X Window System (X for short); Linux’s GUI environment.
often moved to /usr/bin
/opt
intended for ready-made packages that don’t ship with the OS; such as commercial word processors or games.
static and shareable
Some system administrators break it into a separate partition
/home
contains users’ data; and it’s shareable and variable
/root
home directory of the root user
variable; not shareable
/var
contains transient files of various types—system log files; print spool files; mail and news files; and so on
variable; some subfolders are shareable and some are not
Many system administrators put /var in its own partition; particularly on systems that see a lot of activity in /var ; like major Usenet news or mail servers.
/tmp
temporary files
variable; seldom shared
/mnt
removable-media devices
/media
like /mnt ; but it should contain subdirectories for specific media types
/dev
files that represent devices
/proc
virtual filesystem that’s created dynamically by Linux to provide access to certain types of hardware information that aren’t accessible via /dev
/etc/updatedb.conf
the configuration file for updatedb used by locate
/boot/efi
EFI System Partition (ESP)
/boot/grub/menu.lst
/boot/grub/grub.conf
grub legacy configuration file
/boot/grub/grub.cfg
do not edit
grub 2 configuration file
etc/grub.d/
grub 2 OS probers
/etc/default/grub
grub 2 menu configuration
/var/log/messages
syslogd output
/var/log/syslog
i think this is also syslogd output
/sbin/init
the first program run by the kernel
/etc/inittab
id: runlevels:action:process
e. g.
l0: 0:wait:/etc/init.d/rc 0
l1: 1:wait:/etc/init.d/rc 1
the programs the init script is supposed to run when changing runlevels
also specifies the default runlevel
/etc/init.d/rc
or /etc/rc.d/rc
the program that runs all of the scripts associated with the desired runlevel
/etc/rc.d/rc?.d
or /etc/init.d/rc?.d or /etc/rc?.d
S* scripts are started
K* scripts are stopped
scripts that are run by rc when the runlevel changes
/lib/systemd/system
configuration files for systemd
/etc/init/
Upstart and it’s scripts
