Basic GNU/Linux Commands

Command

Descriptions

alias

Allows you to set aliases and view the current aliases.

awk

Search for a pattern within a file.

alien

Converts .tgz and rpm’s to .deb format.

banner

Prints characters as a poster.

badblocks

Searches a device for bad blocks.

biff

Turns mail notification on and off.

bg

move a job running in the foreground to the background.

bzip2

Used to compress and decompress files. Similar to gzip.

cardctl

Used to control PCMCIA cards.

cfdisk

Used to partition a hard disk.

cp

Copy

chattr

Changes the attributes of a file or folder.

chroot

Change the root directory for a command.

chmod

Used to change permissions on a directory or file.

chown

Used to change the owner of a file or directory.

chgrp

Used to change the group a file belongs to.

clear

Clears the screen

cpio

Copies file.

cat

Displays the content of a file

chpasswd

Used to change a large number of passwords at once.

cd

Changes directories.

chage

Sets password aging parameters.

cal

Displays a calendar.

cron

Used to execute commands at a certain time.

crontab

Allows you to view or edit the current cron jobs.

dselect

A graphical front end for dpkg.

dpkg

Installs packages on debiann distro’s.

date

Prints current date to the screen

du

Lists disk usage in a directory.

df

Reports disk usage information. df -h

dmesg

Used to view the kernel boot file.

dump

Used for backing up.

edquota

Sets quotas for specific users.

env

Lists current environment variables.

fdisk

Used to create/edit/delete partitions.

fsck

Checks a file system for consistency.

fg

Used to send jobs to the background.

fuser

Checks to see what processes and users have open files.

find

Searches for a file.

free

Will show total memory, used memory, and free memory.

gcc

Used to compile C, Assembler, and Pre-processed C source.

gpasswd

Used to set a password for a group.

grep

Used to search through a file for a specified pattern.

getty

Set terminal type, modes, speed, and line discipline

groupadd

Create new group account.

groupdel

Deletes a group.

groupmod

Used to modify a group.

groups

Shows what groups a user is part of.

gunzip

Uncompress files compressed by gzip.

head

Displays the first 10 lines of a file to the screen.

hdparm

Gets disk information.

history

Lists recently executed commands.

host

Used to get DNS info.

htpasswd

Allows you to set usernames and passwords for your websever.

id

Display information about yourself or another user.

insmod

Installs modules.

init

Used to change run levels.

isapnp

Sets up ISA cards.

icmpinfo

Intercept and interpret ICMP packets

jobs

Used to show jobs running in the background.

join

Join lines of two sorted.

kill

Used to kill a process.

killall

Kill processes by command name.

kernelcfg

A graphical application configures Linux.

klogd

Control which kernel messages.

linuxconf

A command line GUI which lets you configure your linux

lpc

Used to control a line printer.

lpq

View the print spool queue.

lpr

Send files to the printer spool queue.

ls

Displays a directories contents.

ln

Used to create hard and symbolic links.

less

Display the contents of a file

locate

Search for a file or directory.

ldd

Shows what shared libraries a program is dependent on.

ldconfig

Used to configure/view shared libraries.

last

Lists logins and reboots.

lastlog

Print the last login times for system accounts.

lsmod

Lists loaded modules.

lsattr

Lists the attributes for a file or folder.

logrotate

Used to manipulate log files.

mount

Used by itself, reports the currently mounted files.

modinfo

Give info about the module.

modprobe

Queries modules.

man

Displays the Man page for a given command.

mesg

Used to allow/not allow ‘write’.

manpath

Attempts to determine the path to a man page.

mail

Used to send and receive mail.

mkdir

Make directory

mke2fs

Used to format a partition with the Ext2 file system.

mv

Move/Rename

merge

Merge multiple files together.

more

Lets you page through text one screen full at a time.

minicom

Great utility for troublshooting a modem.

mkbootdisk

Used to make a boot disk.

ntsysv

Used to select what services should automatically start.

nice

Used to set process priorities.

nslookup

Used to get DNS info from name servers.

netstat

Shows active sockets.

ps

Displays current processes

ping

Used to test connectivity between two hosts.

pwd

Present Working Directory

pwconv

Used to set up the /etc/shadow file.

pnpdump

Determines settings for existing ISA cards.

quota

Allows users to view their own disk quotas.

quotaon

Turns on disk quotas for the system.

quotaoff

Turns off disk quotas for the system.

repquota

Provides reports of disk usage for various users.

rmmod

Removes modules.

rm

Remove

rmdir

Remove directory

rpm

(RedHat flavors only)Used to install RPM’s

rpcinfo

Used to see what rpc services are available.

route

Used to view/change routes between you and other hosts.

smbclient

Used to connect to Windows shares or Samba.

smbadduser

Maps linux user names to Windows NT user names.

smbpasswd

Used to update the smbpasswd file with new accounts.

set

Used to read and write variables.

setquota

Used to set disk quotas.

sort

Sorts lines in a file by alphabetical order.

sndconfig

Used to probe and configure a sound card.

su

Change to Super User (root).

spell

Checks for spelling errors in a file.

startx

Start the X Server (GUI)

shutdown

Shutdown machine

suspend

Places a shell in the background.

showmount

Shows mount information for an NFS server.

swapon

Turns on the swapfile.

swapoff

Turns off the swapfile.

testparm

Used to troubleshoot Samba.

tar

Used to compress multiple files.

timeconfig

Used to set the timezone on your machine.

tac

View a file from the last line up.

touch

Creates an empty file.

tail

Displays the last 10 lines of a file to the screen.

talk

Used to chat with another user on the same machine.

tr

Converts one set of characters to another.

traceroute

Used to track the path a packet takes to a host.

top

Shows information about the most CPU-intensive Apps.

useradd

Add a user.

usermod

Modify a user.

userdel

Delete a user.

umount

Removes a device from the filesystem.

updatedb

Updates the locate database.

uname

Determines OS name, version and machine name.

vmstat

Lists information on memory usage.

vi

A text editor

whereis

Finds documentation files.

who

Tells you who is logged into your server.

whoami

Tells you your user information.

wc

Print the number of bytes, words, and lines in files

which

Finds the full path for a command.

write

Used to send a message to another user.

whois

Used to query servers for info on.

wall

Writes a message to all logged in users.

xman

Graphical interface for man pages.

xf86config

Used to configure X.

zcat

Read files that have been compressed with gzip