LINUX BASIC COMMAND

A summary of useful Linux commands

Starting & Stopping

shutdown -h now Shutdown the system now and do not reboot

halt Stop all processes - same as above

shutdown -r 5 Shutdown the system in 5 minutes and reboot

shutdown -r now Shutdown the system now and reboot

reboot Stop all processes and then reboot - same as above

startx Start the X system

Accessing & mounting file systems

mount -t iso9660 /dev/cdrom/mnt/cdrom Mount the device cdrom and call it cdrom under the /mnt directory 

mount -t msdos /dev/hdd/mnt/ddrive Mount hard disk “d” as a msdos file system and call it ddrive under the /mnt directory

mount -t vfat /dev/hda1/mnt/cdrive Mount hard disk “a” as a VFAT file system and call it drive under the /mnt directory

umount /mnt/cdrom Unmount the cdrom 

Finding files and text within files

find / -name fname Starting with the root directory, look for the file called fname

find / -name ”*fname*” Starting with the root directory, look for the file containing the string fname

locate missingfilename Find a file called missingfilename

using the locate command - this

assumes you have already used the command updatedb (see next)

updatedb Create or update the database of files on all file systems attached to the linux root directory which missingfilename Show the subdirectory containing the executable file called missingfilename

grep textstringtofind/dir Starting with the directory called dir, look for and list all files containing textstringtofind 

The X Window System

xvidtune Run the X graphics tuning utility

XF86Setup Run the X configuration menu with automatic probing of graphics cards

Xconfigurator Run another X configuration menu with automatic probing of graphics cards

xf86config Run a text based X configuration menu 

Moving, copying, deleting & viewing files

ls -l List files in current directory using long format

ls -F List files in current directory and indicate the file type

ls -laC List all files in current directory in long format and display in columns

rm name Remove a file or directory called name

rm -rf name Kill off an entire directory and all it’s includes files and subdirectories

cp filename/home/dirname Copy the file called filename to the /home/dirname directory 

mv filename/home/dirname Move the file called filename to the /home/dirname directory

cat filetoview Display the file called filetoview 

man -k keyword Display man pages containing keyword 

more filetoview Display the file called filetoview one page at a time, proceed to next page using the spacebar head filetoview Display the first 10 lines of the file called filetoview

head -20 filetoview Display the first 20 lines of the file called filetoview

tail filetoview Display the last 10 lines of the file called filetoview

tail -20 filetoview Display the last 20 lines of the file called filetoview

Installing software for Linux

rpm -ihv name.rpm Install the rpm package called name rpm -Uhv name.

rpm Upgrade the rpm package called name

rpm -e package Delete the rpm package called package

rpm -l package List the files in the package called package

rpm -ql package List the files and state the installed version of the package called package

rpm -i --force package Reinstall the rpm package called name having deleted parts of it (not deleting using rpm -e)

tar -zxvf archive.tar.gz or tar -zxvf archive.tgz  Decompress the files contained in  the zipped and tarred archive called  archive

./configure Execute the script preparing the installed files for compiling  

User Administration

adduser accountname Create a new user call accountname

passwd accountname Give accountname a new password

su Log in as superuser from current login

exit Stop being superuser and revert to normal user

Little known tips and tricks

ifconfig List ip addresses for all devices on the machine

apropos subject List manual pages for subject

usermount Executes graphical application for mounting and unmounting file

systems

/sbin/e2fsck hda5 Execute the filesystem check utility on partition hda5

fdformat /dev/fd0H1440 Format the floppy disk in device fd0

tar -cMf /dev/fd0 Backup the contents of the current directory and subdirectories to multiple floppy disks

tail -f /var/log/messages Display the last 10 lines of the system log.

cat /var/log/dmesg Display the file containing the boot time messages - useful for locating problems. Alternatively, use the dmesg command.

* wildcard - represents everything. eg. cp from/* to will copy all files in the from directory to the to directory

? Single character wildcard. eg. cp config.? /configs will copy all files beginning with the name config. In the current directory to the directory named configs.

[xyz] Choice of character wildcards. eg. ls [xyz]* will list all files in the current directory starting with the letter x, y, or z.

linux single At the lilo prompt, start in single user mode. This is useful if you have forgotten your password. Boot in single user mode, then run the passwd command.

ps List current processes

kill 123 Kill a specific process eg. kill 123

Configuration files and what they do

/etc/profile System wide environment variables for all users.

/etc/fstab List of devices and their associated mount points. Edit this file to add cdroms, DOS partitions and floppy drives at startup.

/etc/motd Message of the day broadcast to all users at login.

etc/rc.d/rc.local Bash script that is executed at the end of login process. Similar to autoexec.bat in DOS.

/etc/HOSTNAME Conatins full hostname including domain.

/etc/cron.* There are 4 directories that automatically execute all scripts within the directory at intervals of hour, day, week or month.

/etc/hosts A list of all know host names and IP addresses on the machine.

/etc/httpd/conf Paramters for the Apache web server

/etc/inittab Specifies the run level that the machine should boot into.

/etc/resolv.conf Defines IP addresses of DNS servers.

/etc/smb.conf Config file for the SAMBA server. Allows file and print sharing with Microsoft clients.

/etc/X11/XF86Config Config file for X-Windows.

~/.xinitrc Defines the windows manager loaded by

X. ~ refers to user’s home directory.

File permissions

If the command ls -l is given, a long list of file names is displayed. The first column in this list details the permissions applying to the file. If a permission is missing for a owner,

group of other, it is represented by - eg. drwxr-x—x 

Read = 4

Write = 2

Execute = 1

File permissions are altered by giving the chmod command and the appropriate

octal code for each user type. Eg chmod 7 6 4 filename will make the file called filename R+W+X for the owner, R+W for the group and R for others. chmod 7 5 5 Full permission for the owner, read and execute access for the group and others. chmod +x filename Make the file called filename executable to all users.

X Shortcuts - (mainly for Redhat) 

Control|Alt + or - Increase or decrease the screen resolution. eg. from 640x480 to 800x600

Alt | escape Display list of active windows

Shift|Control F8 Resize the selected window 

Right click on desktop background Display menu

Shift|Control Altr Refresh the screen

Shift|Control Altx Start an xterm session 

Printing

/etc/rc.d/init.d/lpd start Start the print daemon

/etc/rc.d/init.d/lpd stop Stop the print daemon

/etc/rc.d/init.d/lpd status Display status of the print daemon

lpq Display jobs in print queue

lprm Remove jobs from queue

lpr Print a file

lpc Printer control tool

man subject | lpr Print the manual page called subject as plain text

man -t subject | lpr Print the manual page called subject as Postscript output

printtool Start X printer setup interface

~/.Xdefaults Define configuration for some Xapplications.

~ refers to user’s home

Print This Page

Ubuntu Basic Command List