Linux-command-list: Difference between revisions

From ITCwiki
Jump to navigation Jump to search
(Created page with '= An Alphabetical List of Linux Commands = == A == ; Anacron : Similar to Cron, this command runs commands periodically, with a frequency specified in days ; apt : short for …')
 
No edit summary
Line 1: Line 1:
= An Alphabetical List of Linux Commands =
= An Alphabetical List of Linux Commands =



Revision as of 05:05, 16 December 2010


An Alphabetical List of Linux Commands

A

Anacron
Similar to Cron, this command runs commands periodically, with a frequency

specified in days

apt
short for Advanced Package Tool this utulity is used to manage software

packages popular in debian distros. This package uses several front ends such as

aptitude, apt-get, and symantec

aptitude
This is part of the Apt package. Used to manage software.
arp
Arp is a networking command. Used to display or manipulate the Linux Kernel's

IPv4 network neighbour cache. e.g. it relates IP adresses to Mac addresses.

at
Executes commands at a specified time.
atd
runs jobs queued by at
atq
Lists users pending jobs, if the user is the superuser everybodies job's are

listed.

atrm
deletes jobs using a job number to specify the job

B

bash
bash is the standard linux shell for almost all popular distros. The shell

interprets all other commands.

batch
executes commands when load levels permit as specified atd
bzip
A file compression utility, like gzip, but with better compression

C

cat
Short for concatenate this program reads files and prints to standard output.
cfdisk
A hard drive partitioning tool.
chage
this command allows you to change information related to user passwords. i.e.

when a password will expire.

chattr
modifies file permissions in a way similar to chmod.
chkconfig
manages which services will run in a specified runlevel
chmod
changes the permissions for one or more files.
chown
changes the ownership of one or more files both for the user and or the group.
chpasswd
changes the password for a user.
chroot
changes the root directory for a program, or for the users shell
cksum
Runs a CRC checksum for all specified files. Used to verify that a file was not

altered or corrupted during transfer.

clear
has the same effect as pressing ctrl and L. This clears your terminal of all

output.

cp
This command is used to copy files or directories to another locations.
cpio
this is an archiving tool similar to tar. intended to copy archive files to

tape, or disk.

crond
Executes commands at scheduled times as controlled by crontab
crontab
at it's most basic level, crontab allows you to edit your crontab file. This is

the file that controls what commands are set to run at a specific time.

cupsd
starts the print scheduler.
cut
allows you to cut information out from the specified files.
cvs
short for concurrent versions system allows multiple users to change, and

implement their changes to files concurrently.

D

date
Prints the current date and time, this can also be used by administrators to

change the date and time of the clock. See also hwclock.

dd
short for data dump this command makes a bit for bit copy of a specified

location. Though it can be a very powerful tool, this would not be used for

standard backup, or data manipulation.

df
Gives the available disk space of all mounted partitions, or on a specified

mounted partition.

diff
Used to show the differences between two files.
dig
Used to lookup DNS servers similar to the deprecated nslookup command.
dir
The same command as ls, even taking the same arguments. This command may not

necessarily be part of your distro, but exists for simplicity of people familiar

with Microsoft command line.

disable
disables access to a printer.
dmesg
a powerful troubleshooting command, this command displays the messages from the
kernel ring buffer meaning the information that flys by while your system is 

booting.

domainname
used to view or set the computers domain name.
doexec
executes the specified command with defined options, and arguments.
du
prints current disk usage for the specified location.
dosfsck
similar to fsck, but used for dos filesystems. This command attempts to

diagnose, and fix common filesystem errors.

dump
this is a backup utility available for specific linux filesystems that can

perform incremental backups after an initial full backup.

E

e2fsck
similar to fsck or dosfsck, this command is used to diagnose and attempt repairs

to a file system. Used for ext2 and ext3 systems.

echo
prints input as standard output. Also can be used to view environmental

variables.

edquota
allows you to edit filesystem quotas.
egrep
searches for lines that contain an extended regular expression.
enable
enables printers.
env
displays all environment variables this command can also be uses to change

environment variables .

expand
Converts tabs in files to defined number of spaces.

F

factor
displays the prime number of specified number.
false
This command returns an unsuccesful status. Peticularily useful in scripts.
fdisk
used to view, and edit partitions, and to change active partitions.
fetchmail
gets email from mailservers, and forwards it to the local system
fgrep
a variant of the grep command, this command searches for information that

matches the user defined input. This command is faster than grep, but may not be

as powerful.

file
gives information about the type of data the specified file contains.
find
A search utility for linux that can search by a number of different types of

data. e.g. name, type, or size.

finger
gives information about specified users
fmt
a command that can help unify formatting of text.
fold
breaks the lines of a file. ie. you can format a text file to only be a set

number of characters, bytes, or columns.

free
gives information about current RAM, and swap space usage.
fsck
checks and repairs damaged filesystems.

G

gpasswd
changes specified group password.
gpg
Stands for Gnu Privacy Guard. This command allows encryption and decryption of

data.

grep
This utility can be used to search for text within a file. When piped with

other commands it is very powerful.

groupadd
Creates new groups
groupdel
deletes groups from the system
groupmod
Modifies group information
groups
Shows the groups to which a user belongs
gs
Stands for GhostScript. This command is used to interpret Adobe's PostScript

and PDF filetypes.

gunzip
Used to unzip files compressed with gzip
gzexe
used to compress executable files.
gzip
used to compress files.

H

halt
Turns of the computer.
head
Prints the first several lines of specified files.
host
Gives information about hosts, or zones contained in DNS
hostname
sets or displays the current name of the host system.
hwclock
views or changes the hardware clock. See also date command.

I

iconv
converts files to a different character encoding
id
displays information about specified user
ifconfig
view, assigns or configures network interfaces and their addresses along with

other information.

inetd
A linux superserver for internet services.
info
an interactive screen which can give information about many linux commands,

directories, and other valuable linux information.

init
Command used to initialize the system, and change runlevels.
insmod
loads the specified file into the kernel. Not as robust as modprobe.
iptables
can be used to specify IP rules, and potentially build a firewall.

J

join
joins information in files to matching fields such as a line number.

K

kernelversion
gives information about the kernel you are using
kill
terminates process ids or PIDs
Killall
kills all processes related to specified command name.
klogd
allows you to specifiy what kernel messages are displayed, and prioritize them.

L

last
Displays a list of the most recent logins.
lastlog
display the last login times for system accounts
less
pages files or output, is much more robust than the more command. less is more.
lftp
A file transfer program that can use ftp, http, ftps, and https protocols.
ln
Creates hard or soft links to files.
locale
Displays current locale settings.
locate
searches a database of file names. database is updated by updatedb command.
logger
Adds information to the system log.
login
Logs into the system
logrotate
used to rotate, and otherwise manipulate log files.
lpq
checks for the status of print jobs.
lpr
sends files to be printed.
lprm
allows for the cancelling of print jobs.
ls
lists the specified directory.
lspci
lists attached PCI devices
lsof
Lists open files and information about the open files.
lsmod
Lists loaded modules.
lsusb
lists USB devices.

M

mail
a command used for reading and sending mail to other users.
mailq
shows messages currently in the mail queue
man
shows the help manual for specified command
mkdir
creates directories.
modinfo
gives information about the specified module
modprobe
attempts to load a module, as well as all modules original module depends on.
more
pages files or other input
mount
tries to mount the specified drive.
mv

Used to move, or rename files or directories.

N

netstat
a command used to give information on active ports, and other network

information

newgrp
changes users default group.
nice
allows for the priority of a command to be raised or lowered
nslookup
looks up domain nameservers. Has been replaced with dig and host commands.

O

P

passwd
allows the creation or changin of a password associated with a user
paste
merges lines of files into tab-separated columns
pidof
Show the process IDs of the requested program
ping
used to test network connectivity. displays basic information on requested ip

address, and response times.

pr
prepares a text file for a printer friendly format.
ps
shows information about running processes.
pwd
Prints the entire path of the current working directory.

Q

quota
displays information on specified user and group disk quotas.
quotacheck
checks and corrects disk quota information. Usually ran at startup
quotaon
turns on the disk quota requirements.
quotaoff
turns of the disk quota requirements.
quotastats
displays disk quota information

R

reboot
reboots the system.
reject
tells printing system to reject specified destinations
renice
changes the priority of already running processes
repquota
creates a report for diskusage and quotas on the specified disk.
reset
essentially the same as hitting the reset button, but this command is limited

to the terminal

restore
restores backup files from a dump. See also dump.
rm
deletes files, and if passed the correct option, directories also.
rmdir
deletes directories, but not not the files they might contain.
rmmod
uninstalls modules from the kernel, generally you would want to use modprobe

instead.

route
allows the addition or deletion of entries in the routing tables.
rpm
the red hat package manager. Used to install, upgrade, and uninstall packages.
rsync
used to transfer files, typically accross a newtork.
runlevel
displays runlevel information

S

scp
used to securely transfer files.
sed
Sed is a stream editor used to make basic changes to an input stream.
seq
this command is used to print one incremental number per line to standard

output.

setquota
used to set a diskquota
sftp
a secure file trasfer protocol that can be used via command line.
sh
the standard unix shell.
shred
securely overwrites, and deletes files.
shutdown
used to shutdown the computer. Can be set to shutdown in a certain amount of

time, or at a certain time.

size
shows the six of a file
sleep
defines a period of time the computer shou wait before processing another

command

ssh
Used to logon securely to another server, and run commands.
ssh-add
Adds identities the the authentication agent.
ssh-agent
Used to hold private key for use with public key authentication
ssh-keygen
Used to generate and manage authentication keys for SSH.
ssh-keyscan
uses to gather public and private keys from other hosts.
stat
displays file or system status
su
Switches User, if no user is given attempts to become superuser.
sudo
Gives access to execute command as another user
sum
creates a checksum for the specified file
swapoff
disables devices for swapping
swapon
enables devices for swapping

T

tail
Displays the last 10 lines of requested files
talk
a basic chat program
tar
This command stands for tape archiving. It is used to copy or restore files from
tape or disk
tcpd
command to monitor incoming requests for specific services
tcpdump
this command allows you to dump tcpip information to a medium to be examined.
telnet
allows logging into another system remotely, and executing commands
tftp
allows users to transfer files to and from remote machines.
top
top provides information about the most cpu intensive processes running.
touch
creates files, and or can update access and modification times of a file.
tr
stands for translates character, and does just that, translating the characters

you specify into another set of characters you specify.

tracepath
traces the path to the specified host. Not as robust as traceroute
traceroute
traces path to specified host.
true
a command that returns a successful status.

U

umount
unmount the specified filesystem
uname
displays information about the machine and operating system
uptime
prints information about the current sessions.
useradd
creates new user accounts.
userdel
deletes specified ser accounts
usermod
allows for modification of user accounts.

V

vi
a text editor
vmstat
gives information on virtual memory

W

w
gives information on currently logged in users, and their activities.
warnquota
used to set the why and who of to email when a user reaches their soft quota

limit.

wget
used for basic file downloading over the web
whatis
A way to search for linux commands from the command prompts.
whereis
locates the source and manual pages for linux commands and files.
which
lists the pathnames of the files that would be executed if the specified

command had been run.

who
shows who is logged into the system
whois
searches whois for information on a domain name, or IP
write
a way to initiate or respond to an interactive conversation with another user

X

xargs
builds and execute command lines from standard input.
xinetd
A linux Superserver that listens to tcpip requests on behalf of other programs.

Y

yes
repeatedly outputs a line with specified strings, or just a y if unspecified.

Used mostly in scripts.

Z