LPIC-1 Exam 101

/var/log/messages

contains detailed post boot messages for your system as well as messages/errors/information from applications that communicate with your kernel, kernel mods

rpm2cpio

convert RPM packages to CPIO compressed files

pr

convert files for printing

unexpand

converts spaces to tabs

expand

converts tabs to spaces

cp

copies files and directories

fdisk

command to partition a disk with MBR partitions

umount

command to unmount specified filesystem

xargs

command used to build and execute command

uname -p

prints processor info

pwd

prints working directory

/etc/fstab

configuration file containing persistent filesystem mounts

dpkg -configure

configures a Debian package

&&

command1 __ command2; operand used to ensure that command2 runs only if command1 returns with status 0

debugfs

interactively modify a file system

/proc

Contains virtual system information.

SIGHUP

1 HANGUP signal

SIGTERM

15 TERMINATION SIGNAL

SIGINT1

2 INTERRUPT FROM KEYBOARD signal

SIGKILL

9 KILL signal

LD_LIBRARY_PATH

Bash environment variable that determines additional library locations to be searched when looking for shared libraries

run level 2

DEBIAN - multi-user mode with X running and a graphical login OTHER - undefined

run level 3

Full multi user mode with no graphical login

shutdown -P

Half action to turn off power

ls | grep "(this"

Quotes remove regex.

run level 1

RN for single usermode. for low level maintenance

run level 0

RN to shutdown/poweroff system

/etc/apt/sources.list

Stores repository locations that apt uses to search for packages

run level 4

Undefined or available for user defined run level

gzip/gunzip

compression utility commonly used in conjunction with tar

/boot/grub/menu.lst

config file for GRUB legacy

lsusb

a utility for displaying the information about USB buses and associated connected devices in the system. by default, reads the /dev/bus/usb directory for contents and configs

touch -a

access time only on a file

nl

add line numbers to a file for display or redirect to another file

tune2fs

allows you to change the file system parameters such as: maximum mount count, time between checks, add a journal, set desire reserve blocks. filesystem cannot be mounted

renice

alter the priority of running process

tar -r

append files to end of tar archive

tar -A

append tar files to an archive

fsck -a

attempt to automatically repair all errors in a filesystem

modprobe

automatically loads any dependent modules and is usually the preferred way of loading kernel modules

/boot/grub(2)/grub.cfg

config file for GRUB2

boot process

bios > POST > MBR > boot loader > kernel > init/systemd

dd

bitwise copy of file file, converting and formatting according to operands.

mkfs

command to build a linux file system on a device

init

can be used to change runlevels of machine. last process to be run in boot process

killall

can be used to kill all processes of a certain name

shutdown

can be used to power off the machine but can notify users before doing so for a set period of time

kill

can be used to stop executing process, uses PID

shutdown -c

cancel any pending shutdown

jobs

command to display minimal information about processes associated with the current session

xfs_info

command to obtain xfs filesystem info

touch -m

change only modification time of a file

runlevel

check previous and current runlevel

fsck

checks and repairs filesystems on unmounted devices

rpm -K

checks signature on rpm package

mount

command that attempts to mount filesystems to directories

updatedb

command that updates location database. must be run before locate

tee

command that will save stdin to a file as well as send it to stdout

join

join lines of two files based on a common field or delimitor

cpio -d

create leading directories where needed in cpio archive

mke2fs

creates an EXT2/3/4 filesystem

tar --delete

delete file from tar archive

file

determine file type

rpm -qf

determine which installed rpm package a file belongs to

/etc/yum.repos.d

directory containing yum source repo files

top

display linux processes (memorize commands associated when in it)

which

display path the indicated command is in (if in PATH variable)

/proc/dma

displays DMA addresses in use on the system

df

displays the filesystem usage but not a breakdown within a filesystem

wc

displays word count of file

mv -f

do not prompt overwrite when moving files

fsck -N

dont execute repair when scanning filesystem, just show what would be done

dmesg

kernel ring buffer info. prints number of messages on the screen that display info about the hardware devices that the kernel detected during boot

od

dump files in octal format

edquota

edit a user quota

swapon

enable swap on a designated partition

rpm -e

erase or uninstall rpm package

du -h

estimate file space usage in human readable format

rpm2cpio file.rpm | cpio -dium

extract files from rpm package without installing the rpm package

tar -x

extract files from tar archive

cpio -i

extract from cpio archive

dmesg

extracts information about the boot process and can be viewed with the command directly

ldconfig

program to clear the library cache after adding library locations to the /etc/ld.so.conf file

tar -j

filter tar archive through bzip2

tar -z

filter tar archive through gzip

tar -J

filter tar archive through xz compression

tar -d

find differences between tar archive and file system

locate

find files by name, uses the location database

find

find files on the local or any mounted filesystem

uptime

find uptime and display load avg

shutdown -F

force fsck on next boot

run level 5

graphical multi-user runlevel

shutdown -h

halt or power off the system

grep -i

ignore case when searching for term

dpkg -i

installs .deb packages

rpm -i

installs rpm package

rpm --nodeps

installs rpm package without worrying about installed dependencies

mv -i

prompt for overwrite when moving files

id:2:initdefault:

line in /etc/inittab that configs the default runlevel

rpm -qpl

list all files in an rpm package on disk

dpkg -c

list contents of a debian package

tar -t

list contents of a tar archive

rpm -ql

list files in an rpm installed package

rpm -l

list files in an rpm package

lsmod

list modules currently loaded by the running Linux kernel

dpkg -s

list status of debian package (installed or not)

whereis

locates the sources/binary and manuals section for specific files. uses PATH variable

/etc/updatedb.conf

location database configuration file

tar -c

make a new tar archive

mkdir

makes directory

uname -o

prints operating system name

man 1

manual for executable programs or shell commands

man 5

manual for file formats and conveentions

man 6

manual for games

man 9

manual for kernel routines

man 3

manual for library calls

man 7

manual for misc

man 4

manual for special files

man 8

manual for sys admin commands usually only for root

man 2

manual for system calls

paste

merge lines of files

mount -a

mount all file systems mentions in /etc/fstab

mv -n

move but with no clobber set

mv

moves files and directories

dumpe2fs

obtains filesystem information for ext2/ext3/ext4

insmod

older method to insert modules into running kernel

rmmod

older method used to remove modules from kernel

tar -u

only appends files newer than the copy in tar archive

uniq -d

only print duplicate lines between 2 files

uniq -u

only print unique lines between 2 files

head

output the first part of a file

tail

output the last part of file

apt-get

package handling and installation utility for Debian based distros

uname -a

print all info of a system kernel

rpm -qa

print all installed rpm packages

grep -v

print all lines not matching search patter

ldd

print shared library dependencies for the indicated program or file

ps -ef, ps aux

prints all currently running processes on the system

uname -i

prints hardware info

dpkg --info

prints information on a debian package not installed in the system

uname -s

prints kernel name

uname -r

prints kernel release

uname -v

prints kernel version

uname -m

prints machine/cpu info

uname -n

prints node name

0x0c

typecode for FAT disk

0x83

typecode for Linux file system

rpm -f

query rpm package owning file

rpm -q

query rpm package to see if already installed

shutdown -r

reboot after shutdown

rpm --rebuilddb

rebuilds rpm database

rpm --rebuild

rebuilds source rpm package

dpkg-reconfigure

reconfigures an already installed debian package

fmt

reformats streams or files for display as indicated (width of columns)

dpkg -r

remove Debian package

swapoff

remove device mounted on swap

cpio -u

replace all files without asking in cpio archive

sed 's/ugly/beautiful/g' myfile.txt

replace all instances of 'ugly' with 'beautiful' in myfile.txt

uniq

report or omit repeated lines

BIOS

responsible for preparing the system to boot, finding the CPU, memory and disk in order to begin the boot process

bg

restores a job to the running status but in the background

cpio -m

retain previous modification times when creating files in cpio archive

0x82

typecode for Linux swap partition

nohup

run a command immune to hangups, without output to console or non-tty

nice

run a program with modified scheduling priority

/etc/inittab

run level and default run level config is set by the contents of this file on SYSVINIT systems. OR pointer to systemd start config in /lib/systemd/system/<target name>.target

run level 6

run level for reboot

0x0f

typecode for newer type of extended partition

0x07

typecode for ntfs

rpm --checksig

same as rpm -K

fgrep, grep -F

search for a literal sequence of strings

egrep, grep -E

search for extended regular expression in a file

rpm -a

selects all rpm packages

rpm -p

selects given rpm package on disk

shutdown -k

send warning of impending shutdown but not shutdown

fg

sends program to the foreground

env

show current session environment variables

free

show free memory and swap

/proc/interrupts

shows the IRQs in use on the system

shutdown -f

skip fsck on next boot

sort

sort forward/reverse contents by alpha/numeric characters

split

split a file into pieces

/etc/ld.so.conf

stores shared library paths for caching with ldconfig

sed

stream editor for filtering and formatting text

repquota

summarizes quotas for a filesystem

0x05

typecode for old type of extended partition

shutdown -t

tell init to wait XX seconds before shutdown

kernel

this is the main part of the Linux operating system, it is responsible for the entire OS, threads, devices, filesystems and video

apt-cache search

to search for debian packages

cat

tool to concatenate files

tr

translate/squeeze/delete characters from standard input writing to standard output

mkswap

turn a filesystem into swap. this is done after creating a new swap partition.

quotaon

turns quotas on

rpm -F

upgrade already installed rpm package

rpm -U

upgrades or installs new rpm package

apt-cache pkgnames

use cache to show installed deb packages

/var

used to contain files that will change frequently

unset

used to remove an environment variable

cut

used to remove sections from each line of files

export

used to set an environment variable

/home

user directories

make

utility to read a source config file and maintain a group of files or programs

rpm -V

verifies rpm package

fsck -A

walk through /etc/fstab file and try to check all file systems