Linux Commands - for beginners

Command

Action

Starting and Stopping

shutdown -h now

shutdown system (don't re-boot)

shutdown -r 5

shutdown system and re-boot in 5 mins

ctrl-alt-delete

Shutdown system (not fully supported)

halt

Shutdown system (not fully supported)

reboot

Shutdown system (not fully supported)

ctrl-c

aborts executed command

ctrl-u

deletes whole command typed

startx

start X (window system) from shell

shft-ctrl-alt-x

start an xterm session

right click on desktop

display menu (when already in X)

alt-F2

issue single command (from within X)

top

list / kill current processes
(or alt-F2 then ktop from KDE)

Working with Files

cd ..

change directory to one above

cd /usr

change directory to /usr

cd /.

changes to highest level

ls

list files in current directory

ls -alprtCFsS

-a=all files, -l=long, -p=directories, -r=reverse order, -t=time, -A=all except for . & .., -C=columns, -F=filetype, -s=size, -S=by size, -R=recursively

alias ls='ls -FAsS --color'

edit ~/.bashrc to make this change

TAB

word completion

pwd

print working directory

*

wildcard for any number of characters

?

wildcard for single character

[a-m]

wildcard for names beginning with a - m

mkdir name

make a new directory called name

rm name /dir

remove file called name from/dir

rm -rf name

remove entire directory, and all subdirectories - take care with this one!!!

rm dir /name

remove directory called name - directory must be empty including .* files

cp filename /home

copy filename to directory /home

mv filename /home

move filename to directory /home

cat filename

display file called filename

which filename

display pathname to executable filename

more filetoview

display filetoview page by page - using spacebar

|

input re-direction (called pipe)

>

output re-direction

cat filename | more

pipe the display through more for reading

man command

display the manual pages for command

man -k keyword

display man pages containing keyword (q=quit)

info command

display info on command

apropos subject

list man pages for subject/word (q=quit)

head filetoview

display first 10 lines of filetoview

tail -20 filetoview

display last 20 lines of filetoview

tail -f /var/log/messages

display last 10 lines of system log

find / -name file

find file starting from the root directory

find / -name "*file*"

find file with string indicated

grep textstring /dir

list all files containing textstring from /dir

File Systems

mount -t iso9660 /dev/cdrom /mnt/cdrom

mount the CDROM under /cdrom directory

mount -t msdos /dev/fd0 /mnt/floppy

mount DOS floppy disk under floppy directory

umount /mnt/cdrom

u(n)mount the cdrom

usermount

graphical mounting program

du

displays disk usage (-a=all files, -s=space of directories)

df

shows disk free space

e2fsck -av /dev/hda1

check and repair filesystem

fdformat /dev/fd0H1440

format a floppy disk

mkfs -t ext2 -m /dev/fd0H1440 1440

make filesystem on floppy

make zdisk

creates boot disk

tar -cvf archive1.tar /usr/parker

compress /usr/parker into archive1.tar

tar -zxvf archive.tgz

decompress zipped and tarred archive

tar -zxvf archive.tar.gz

as above

tar -cMf /dev/fd0

copy current directory to multiple floppies

Printing

cat file >/dev/lp1

print file (ie to test printing interface)

/etc/rc.d/init.d/lpd start

start print daemon (also 'stop')

lpq

display jobs in print queue

man -t subject | lpr

(postscript) print subject's man page

printtool

X based printer setup interface

User Administration

uname -a

Linux version information

adduser account

create a new user account

password account

give account a new password

su

login temporarily as superuser

exit

revert to ordinary user

passwd

change own password

chown ownerfile

change ownership of file

chmod +x file

make file executable to all users

chmod 764 file

user-all, group-read&write, others-read only
(read=4, write=2, execute=1)

dmesg

display bootup messages

rpm -ihv filename.rpm

install package

to install a "tarball" (.tar)

link to instructions

Directories & Configuration files

/bin

executable files

/dev

device files

/etc

configuration files (ending in 'conf' or 'rc')

/etc/fstab

devices and mountpoints

/etc/motd

message of the day

/etc/rc.d/rc.local

equivalent of autoexec.bat

/etc/HOSTNAME

hostname (including domain)

/etc/inittab

runlevel machine boots into

/etc/X11/XF86Config

X-windows configuration file

/home

users files

/lib

shared library files

/lost&found

files restored after crash

/mnt

where external filesystems are mounted

/opt

programs

/proc

'virtual' system files

/root

administrator's files

/sbin

system administration files

/tmp

temporary files

/usr

X based files and other miscellany

/usr/local

where user programs should be installed

/usr/doc

lots of documentation

/var

changing files (variable) ie spools and queues

~/.xinitrc

defines X-window manager for ~ user

Editing Files

with emacs

ctrl-x ctrl-s

saves file

ctrl-x ctrl-c

exits

with vi(m)

esc i

editing mode

esc : w

saves (writes) file

esc : q

quits

esc : w q

write and quit

esc : q !

quit without saving