Linux Dump

-> symbolic link

lrwxrwxrwx. 1 root root 35 Jul 8 2014 .fetchmailrc -> .configs/fetchmail/.fetchmailrc

/etc/apt/sources.list

stores details of the current package repositories stored on a Debian system

telinit

will place the system into single user mode

STDOUT

rmp2cpio sends its output here by default, and therefore that output needs to redirected to a file in most cases.

/root

root's home directory on a Linux system

rpm -v

rpm verbose (lowercase v)

/etc/init.d

scripts are stored in here on a system using SysVinit. You may sometimes find these linked from /etc/rc.d/init.d as well.

/var

should be the largest for a mail server because mail spools are stored within this hierarchy.

Runlevel1

sometimes displayed as runlevel s or S, is single-user mode in which many services are not started.

swap space

space that is used when there is insufficient RAM on a system.

Sticky Bit

special permission can't be assigned to a file. It can only be assigned to directories.

awk -f

tells awk what field separator to use, the option means that the separator is : (colon).

read only

the default for GRUB, will initally mount the root partition as ro and then remount as rw

apt-get upgrade

this command will upgrade the system to the latest version of software for packages already installed.

/proc

this filesystem contains information about currently running processes and additional information about the kernel and current boot of the system

/usr

this hierarchy contains many of the programs that run on a Linux system

exclude

this option can be used to exclude certain packages. The argument accepts wildcards

root=/dev/sda2

this option will cause the given kernel to load the specified location for its root partition.

/lib/systemd/system

unit configuration files are stored here.

yumdownloader

utility that will download an RPM package but not install it. Is part of the yum-utils package.

chkconfig --list

when working with a SysV system, this command will display all services and their runlevels

halt

will initiate an immediate shutdown of the system

0

GRUB begins its count here

7 to 15 devices per bus

How many SCSI devices are supported per bus?

four primary partitions

MBR based disks can be partitioned with up to this many partitions.

initrd

option is used for specifying the initial RAM disk

start

option that configures a service on boot to start immediately

enable

option that configures the service to start on boot

ExecStart

option that indicates the command to be executed on startup of a systemd service

rootnoverify

option that is used to specify a non-Linux kernel, one that GRUB should not attempt to load.

rpm -V

option that will check the files in a given package against versions (or checksums) in the package databae. If no files have been altered, then no output is produced. Note: this is an uppercase V, can also use -verify

noexec

option that will prevent programs that reside on the partition from being executed, used frequently for mounting the /tmp partition

GRUB_DEFAULT

option when used within the /etc/default/grub file, is used to configure the operating system that will boot by default.

84

partition type for an OS/2

dpkg-reconfigure

program that will cause an already-installed package to be reconfigured or changed.

dpkg -r

program that will remove a package

aptitude

provides a terminal based interface rather than the standard command line interface

/etc/udev

Configuration files for udev are found in here.

Sata disks

are addressed as /dev/sdx

sed -g

(also known as global or greedy) will apply the matched operation to the entire line rather than just the first instance of the match.

IRQ (Current interrupt assignments)

/proc/interrupts

/usr/lib/system

Operating system files are typically stored in here

yum list

command that displays information about a specific package

Between 100 MB and 500 MB

The /boot partition will typically be less the allotted amount but should not be undersized. The used space will increase as more kernels are added such as during an upgrade process.

/boot/efi

The EFI system partition will typically be mounted here

runlevel

command that displays the current runlevel for a system.

yum deplist

command that displays the dependencies for the given package.

-i

This option will cause both cp and mv to be interactive, to prompt before overwriting.

ten lines for both

What is the default number of lines printed by the head and tails commands?

Physical volumes, volume group creation, and logical volume creation

What is the logical order for creation of an LVM logical volume?

timestamp of the file will change

What will be the result if the touch command is executed on a file that already exists?

lvcreate

command that is used to create logical volumes with LVM

Shift key

key that if pressed when control has first been handed to GRUB, will cause the GRUB menu to be displayed.

E for editing and B to Boot

Within GRUB pressing these keys will allow you to edit and boot the system once you finish making changes

lspci

a command on Unix-like operating systems that prints ("lists") detailed information about all PCI buses and devices in the system.

/etc/default/grub

can be edited when using GRUB 2 in order to set things like the timeout

dmesg

command displays the contents of the kernel ring buffer. On many Linux distributions, this log is also saved to /var/log/dmesg will typically contain historical messages from the current booting system Common way to find out the location to which the kernel has assigned the drive.

ls

command from with the grub > prompt will show the available partitions

pvcreate

command initializes a physical partition for future use as a logical volume with LVM

sed

command is short for stream editor, is to modify each line of a file or stream by replacing specified parts of the line. It makes basic text changes to a file or input from a pipeline.

set

command that can be used for a variety of purposes to change how the shell environment works.

init 6

command that can be used to access different runlevels. Runlevel 6 is used for rebooting the system.

systemctl status

command that can be used to determine whether a give service is currently loaded.

wall

command that can be used to send a message to all users

lspci -nn

command that displays both numbers and device names

man

command that displays documentation for the command given as the argument.

lsmod

command that is used to list currently loaded modules, if a working device doesn't appear, it typically means that the kernel has a driver already loaded by virtue of being compiled into the kernel itself rather than loaded through a module.

list-units

command that is used to list targets.

lsusb

command that is used to obtain a basic list of USB devices on a system.

uname

command that is used to print system information -a option prints all the information available to uname.

tee

command that is used to send output to standard output and a file.

export

command that is used to set environment variables in Bash.

umount

command that is used to unmount drives within a running system

apt-get

command that is used to work with packages themselves

systemctl

command that is used to work with services and targets.

apt-cache

command that is used to work with the package cache

modprobe

command that loads the module and its dependencies, if applicable

lvmdiskscan

command that looks for physical volumes that have been initialized for use with LVM

initctil reload

command that on a system controlled by Upstart will reload the configuration files

yum -search

command that performs a search of various fields such as the package name and description

wc

command that prints newline, word, and byte counts for each FILE, and a total if more than one FILE is specified.

wc -l

command that provides the number of lines given as input.

dpkg -s

command that searches the given package and provides information about its current status on the system.

update-grub

command that sends its output to STDOUT.

grub-mkconfig -o

command that sends output to a file instead of STDOUT this option can be used to specify a destination file to which output will be sent instead of STDOUT.

grub-mkconfig

command that should be run after making a change to the /etc/default/grub file so that a new configuration file can be created with the changed options.

modprobe -show-depends

command that shows modules that depend on the specified module.

Ldconfig

command that updates the current shared library cache and list. Also reads /etc/ld.so.conf and incorporates any changes found within it.

rm -f

command that will attempt to remove the files without prompting for confirmation, regardless of the file's permissions.

rmmod -w

command that will cause the module to wait until it's no longer in use to unload the module

apt-get update

command that will cause the package cache to be updated by retrieving the latest package list from the package sources.

yumdownload -resolve

command that will download the dependencies of the package being downloaded.

rmmod -f

command that will force immediate removal of module and should be used with caution

rpm -ivh

command that will install a file using rpm, displaying both verbose output and hash marks for progress.

yum install

command that will install a given package

ldd

command that will list the libraries on which the command's argument depends

insmod

command that will load a given module but not its dependencies

env

command that will print the current environment variables and settings from Bash. printenv can also be used for the same purpose.

rm -rf

command that will recursively remove contents of a directory, including other directories.

systemctl get-default

command that will show the default target

rpm -q kernel

command that will show the kernel version. uname -r can also be used for the same purpose.

yum update

command that will update a package

lsusb -t

command the will retrieve information about USB connections on a computer in a tree-like format

isolate

command which on a systemd-controlled system would place the system into a single user mode

set -c

command which prevents output redirection such as that done with > from overwriting a file if the file already exists.

/etc/yum.repos.d

configuration files related to the repositories for YUM are located where?

Coldplug devices

devices that generally must be inserted and removed when the system is powered off. Whereas Hotplug devices are generally described as devices that can be inserted and removed while the system is "hot" or powered on

/proc/bus/usb

directory that contains information about USB devices.

/etc/hotplug/usb

directory that contains scripts that run when a given device is plugged in.

menu.lst and grub.conf

files are used in GRUB Legacy, that is, prior to GRUB 2.

Hotplug devices

generally described as devices that can be inserted and removed while the system is "hot" or powered on, whereas coldplug devices are those that must be inserted and removed when the system is powered off.

Single

given on the Linux kernel command line will boot the system into single-user mode.

dpkg -i

installs a package

/dev/fd0

interface that is typically the first floppy disk in a Linux system.

0.0c

is FAT32

0X83

is Linux

0X07

is NTFS

0X82

is a Linux swap

awk

is the interpreter for the AWK Programming Language. The AWK language is useful for manipulation of data files, text retrieval and processing

modprobe

is used to add loadable modules to the Linux kernel. You can also view and remove modules using this command.

rmmod

is used to remove a module from memory