Special Attributes on files (use "+" to set permissions and "-" to remove)
chattr +a file1	allows write opening of a file only append mode
chattr +c file1	allows that a file is compressed / decompressed automatically by the kernel
chattr +d file1	makes sure that the program ignores Dump the files during backup
chattr +i file1	makes it an immutable file, which can not be removed, altered, renamed or linked
chattr +s file1	allows a file to be deleted safely
chattr +S file1	makes sure that if a file is modified changes are written in synchronous mode as with sync
chattr +u file1	allows you to recover the contents of a file even if it is canceled
lsattr	show specials attributes

Permits on Files (use "+" to set permissions and "-" to remove)
ls -lh	show permits
ls /tmp | pr -T5 -W$COLUMNS	divide terminal into 5 columns
chmod ugo+rwx directory1	set permissions reading (r), write (w) and (x) access to users owner (u) group (g) and others (o)
chmod go-rwx directory1	remove permits reading (r), write (w) and (x) access to users group (g) and others (or
chown user1 file1	change owner of a file
chown -R user1 directory1	change user owner of a directory and all the files and directories contained inside
chgrp group1 file1	change group of files
chown user1:group1 file1	change user and group ownership of a file
find / -perm -u+s	view all files on the system with SUID configured
chmod u+s /bin/file1	set SUID bit on a binary file - the user that running that file gets same privileges as owner
chmod u-s /bin/file1	disable SUID bit on a binary file
chmod g+s /home/public	set SGID bit on a directory - similar to SUID but for directory
chmod g-s /home/public	disable SGID bit on a directory
chmod o+t /home/public	set STIKY bit on a directory - allows files deletion only to legitimate owners
chmod o-t /home/public	disable STIKY bit on a directory

Users and Groups
groupadd group_name	create a new group
groupdel group_name	delete a group
groupmod -n new_group_name old_group_name	rename a group
useradd -c "Name Surname " -g admin -d /home/user1 -s /bin/bash user1	create a new user belongs "admin" group
useradd user1	create a new user
userdel -r user1	delete a user ( '-r' eliminates home directory)
usermod -c "User FTP" -g system -d /ftp/user1 -s /bin/nologin user1	change user attributes
passwd	change password
passwd user1	change a user password (only by root)
chage -E 2005-12-31 user1	set deadline for user password
pwck	check correct syntax and file format of '/etc/passwd' and users existence
grpck	check correct syntax and file format of '/etc/group' and groups existence
newgrp group_name	log in to a new group to change default group of newly created files

Disk Space
df -h	show list of partitions mounted
ls -lSr |more	show size of the files and directories ordered by size
du -sh dir1	estimate space used by directory 'dir1'
du -sk * | sort -rn	show size of the files and directories sorted by size
rpm -q -a --qf '%10{SIZE}t%{NAME}n' | sort -k1,1n	show space used by rpm packages installed sorted by size (fedora, redhat and like)
dpkg-query -W -f='${Installed-Size;10}t${Package}n' | sort -k1,1n	show space used by deb packages installed sorted by size (ubuntu, debian and like)

mount /dev/hda2 /mnt/hda2	mount disk called hda2 - verify existence of the directory '/ mnt/hda2'
umount /dev/hda2	unmount disk called hda2 - exit from mount point '/ mnt/hda2' first
fuser -km /mnt/hda2	force umount when the device is busy
umount -n /mnt/hda2	run umount without writing the file /etc/mtab - useful when the file is read-only or the hard disk is full
mount /dev/fd0 /mnt/floppy	mount a floppy disk
mount /dev/cdrom /mnt/cdrom	mount a cdrom / dvdrom
mount /dev/hdc /mnt/cdrecorder	mount a cdrw / dvdrom
mount /dev/hdb /mnt/cdrecorder	mount a cdrw / dvdrom
mount -o loop file.iso /mnt/cdrom	mount a file or iso image
mount -t vfat /dev/hda5 /mnt/hda5	mount a Windows FAT32 file system
mount /dev/sda1 /mnt/usbdisk	mount a usb pen-drive or flash-drive
mount -t smbfs -o username=user,password=pass //WinClient/share /mnt/share	mount a windows network share

File search
find / -name file1	search file and directory into root filesystem from '/'
find / -user user1	search files and directories belonging to 'user1'
find /home/user1 -name \*.bin	search files with '. bin' extension within directory '/ home/user1'
find /usr/bin -type f -atime +100	search binary files are not used in the last 100 days
find /usr/bin -type f -mtime -10	search files created or changed within 10 days
find / -name \*.rpm -exec chmod 755 '{}' \;	search files with '.rpm' extension and modify permits
find / -xdev -name \*.rpm	search files with '.rpm' extension ignoring removable partitions as cdrom, pen-drive, etc.…
locate \*.ps	find files with the '.ps' extension - first run 'updatedb' command
whereis halt	show location of a binary file, source or man
which halt	show full path to a binary / executable

Files and Directory
cd /home	enter to directory '/ home'
cd ..	go back one level
cd ../..	go back two levels
cd	go to home directory
cd ~user1	go to home directory
cd -	go to previous directory
pwd	show the path of work directory
ls	view files of directory
ls -F	view files of directory
ls -l	show details of files and directory
ls -a	show hidden files
ls *[0-9]*	show files and directory containing numbers
tree	show files and directories in a tree starting from root(1)
lstree	show files and directories in a tree starting from root(2)
mkdir dir1	create a directory called 'dir1'
mkdir dir1 dir2	create two directories simultaneously
mkdir -p /tmp/dir1/dir2	create a directory tree
rm -f file1	delete file called 'file1'
rmdir dir1	delete directory called 'dir1'
rm -rf dir1	remove a directory called 'dir1' and contents recursively
rm -rf dir1 dir2	remove two directories and their contents recursively
mv dir1 new_dir	rename / move a file or directory
cp file1 file2	copying a file
cp dir/* .	copy all files of a directory within the current work directory
cp -a /tmp/dir1 .	copy a directory within the current work directory
cp -a dir1 dir2	copy a directory
ln -s file1 lnk1	create a symbolic link to file or directory
ln file1 lnk1	create a physical link to file or directory
touch -t 0712250000 file1	modify timestamp of a file or directory - (YYMMDDhhmm)
file file1	outputs the mime type of the file as text
iconv -l	lists known encodings
iconv -f fromEncoding -t toEncoding inputFile > outputFile	creates a new from the given input file by assuming it is encoded in fromEncoding and converting it to toEncoding.
find . -maxdepth 1 -name \*.jpg -print -exec convert "{}" -resize 80x60 "thumbs/{}" \;	batch resize files in the current directory and send them to a thumbnails directory (requires convert from Imagemagick)

Linux System Info commands

arch	show architecture of machine(1)
uname -m	show architecture of machine(2)
uname -r	show used kernel version
dmidecode -q	show hardware system components - (SMBIOS / DMI)
hdparm -i /dev/hda	displays the characteristics of a hard-disk
hdparm -tT /dev/sda	perform test reading on a hard-disk
cat /proc/cpuinfo	show information CPU info
cat /proc/interrupts	show interrupts
cat /proc/meminfo	verify memory use
cat /proc/swaps	show file(s) swap
cat /proc/version	show version of the kernel
cat /proc/net/dev	show network adpters and statistics
cat /proc/mounts	show mounted file system(s)
lspci -tv	display PCI devices
lsusb -tv	show USB devices
date	show system date
cal 2007	show the timetable of 2007
date 041217002007.00	set date and time - MonthDayhoursMinutesYear.Seconds
clock -w	save date changes on BIOS

how to repair Install

1. Insert and boot from your WindowsXP CD
2. At the second R=Repair option, press the R key
3. This will start the repair
4. Press F8 for I Agree at the Licensing Agreement
5. Press R when the directory where WindowsXP is installed is shown. Typically this is C:\WINDOWS
6. It will then check the C: drive and start copying files
7. It will automatically reboot when needed. Keep the CD in the drive.
8. You will then see the graphic part of the repair that is like during a normal install of XP (Collecting Information, Dynamic Update, Preparing Installation, Installing Windows, Finalizing Installation)
9. When prompted, click on the Next button
10. When prompted, enter your XP key
11. Normally you will want to keep the same Workgroup or Domain name
12. The computer will reboot
13. Then you will have the same screens as a normal XP Install
14. Activate if you want (usually a good idea)
15. Register if you want (but not necessary)
16. Finish
17. At this point you should be able to log in with any existing accounts.

Magazines

B

	MAGAZINE: BOOT E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: A little more of an advanced magazine, getting more into networking, programming, Java, and lab reports, and is very informative. Also including large amounts of information on CDs included with the magazine. AVERAGE PRICE: $No longer available
	MAGAZINE: Business 2.0 E-MAIL ADDRESS: letters@business2.com WEB PAGE: http://www.business2.com ABOUT MAGAZINE: It's more than a magazine. It goes beyond the sum of its atoms and bits. Challenging you to question every assumption you hold on how business is conducted and to help you rewrite your code. AVERAGE PRICE: $5.00 - $6.00
	MAGAZINE: BYTE E-MAIL ADDRESS: Unknown WEB PAGE: http://www.byte.com ABOUT MAGAZINE: Tells you new products that are planning on coming to the computer market, reviews different products, games, and other programs. AVERAGE PRICE: $4.00 - $5.00

C

	MAGAZINE: C/C++ Users Journal E-MAIL ADDRESS: N/A WEB PAGE: http://www.cuj.com/ ABOUT MAGAZINE: Computer magazine dedicated to articles and columns about the C and C++ programming languages and related topics. AVERAGE PRICE: $2.00 - $4.00
	MAGAZINE: Computer Arts E-MAIL ADDRESS: N/A WEB PAGE: http://www.computerarts.co.uk/ ABOUT MAGAZINE: Computer Magazine that contains information relating to computer graphic design, illustration, 3D, digital video, and much more. AVERAGE PRICE: 3.00 - 4.00GBP
	MAGAZINE: Computer Bits E-MAIL ADDRESS: N/A WEB PAGE: http://www.computerbits.com/ ABOUT MAGAZINE: Computer information magazine that contains various articles relating to the computer industry. AVERAGE PRICE: $20 a year
	MAGAZINE: Computer Games E-MAIL ADDRESS: subscriptions@cgonline.com WEB PAGE: http://www.cgonline.com/ ABOUT MAGAZINE: Computer information magazine that contains various articles relating to the computer industry. AVERAGE PRICE: $3.00 - $4.00
	MAGAZINE: Computer Life / Equip E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Helping you with various information such as with hardware, software, games, reviews, Internet, and more. AVERAGE PRICE: $No longer available
	MAGAZINE: Computer Video E-MAIL ADDRESS: Unknown WEB PAGE: http://www.computervideo.net ABOUT MAGAZINE: Computer magazine dedicated to everything relating to video production and editing, including product reviews, tips, questions and answers, and more. AVERAGE PRICE: $3.00 - $4.00

D

MAGAZINE: DOS WORLD E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Information about DOS, Windows, and related secrets. This magazine and any available copies of the magazine are no longer available. AVERAGE PRICE: $No longer available

I

	MAGAZINE: INTERNET MAGAZINE E-MAIL ADDRESS: N/A WEB PAGE: http://www.zdimag.com ABOUT MAGAZINE: Giving you informative information about the Internet and Intranets, helping you design your web page, how to track your visitors and much more information on each issue. AVERAGE PRICE: $4.00 - $5.00
	MAGAZINE: INTERNET UNDERGROUND E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Tells you about new exciting things happening on the Internet, and gives you links to new web sites popping up on the Internet and links to each web address. This magazine has unfortunately stopped producing any additional copies and is no longer available. AVERAGE PRICE: $No longer available
	MAGAZINE: INTERNET WORLD E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Information about the Internet and new things that are planed to make the Internet a better place for you. New things on the Internet, new tricks in HTML, various Internet information and other computer information. AVERAGE PRICE: $No longer available

L

	MAGAZINE: Linux Format E-MAIL ADDRESS: Click here WEB PAGE: http://www.linuxformat.co.uk/ ABOUT MAGAZINE: Latest news, reviews, features, interviews and tutorials on Linux and each of its distributions. AVERAGE PRICE: 1 year $90US, 83.90 Europe, 96.90 elsewhere
	MAGAZINE: Linux Pro Magazine E-MAIL ADDRESS: Click here WEB PAGE: http://www.linuxpromagazine.com/ ABOUT MAGAZINE: Magazine that includes a full Linux distribution with each release and contains hands on information about Linux and each of its variants. AVERAGE PRICE: 12 Issues including DVD -$99.95

M

	MAGAZINE: Microsoft Certified professional magazine. E-MAIL ADDRESS: mail@mcpmag.com WEB PAGE: http://www.mcpmag.com ABOUT MAGAZINE: For Microsoft Certified Professional or people interested in becoming certified allowing you to write in questions. Testing tips, training locations, and more. AVERAGE PRICE: $4.00 - $5.00
NO PICTURE AVAILABLE	MAGAZINE: MULTIMEDIA WORLD E-MAIL ADDRESS: WEB PAGE: ABOUT MAGAZINE: Tells you about the multimedia world Audio/Video...tells you the best multimedia products out on the market such as Video Cards. AVERAGE PRICE: $4.00 - $5.00

N

	MAGAZINE: Net Guide E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Various information about the Internet, Internet technology, Internet Commerce, popular web sites, and much more. This magazine is no longer being published. AVERAGE PRICE: $No longer available
	MAGAZINE: New Media E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Getting into the media portions of computers such as games, graphic software, animation, virtual reality, and much more. This magazine is no longer being published. AVERAGE PRICE: $No longer available

P

	MAGAZINE: PC Accelerator E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Great magazine with reviews on computer games and hardware, adding great humor and topics appealing to computer gamers. Unfortunately, this magazine is no longer made. The picture shown here was there last issue. AVERAGE PRICE: $No longer available
	MAGAZINE: PC Computing E-MAIL ADDRESS: Unknown WEB PAGE: None ABOUT MAGAZINE: This magazine is now known as Smart Business. AVERAGE PRICE: $7.00 - $8.00
	MAGAZINE: PC GAMER E-MAIL ADDRESS: Unknown WEB PAGE: http://www.pcgamer.com ABOUT MAGAZINE: One of the world's most popular and best-selling PC game Magazines. AVERAGE PRICE: $8.00 - $9.00
	MAGAZINE: PC GAMES E-MAIL ADDRESS: Unknown WEB PAGE: Unknown ABOUT MAGAZINE: Magazine is no longer available AVERAGE PRICE: $No longer available
	MAGAZINE: PC Graphics & Video E-MAIL ADDRESS: Unknown WEB PAGE: http://www.pcgv.com ABOUT MAGAZINE: Getting into more of the graphics and video portions of PCs. Giving such information on digital cameras, graphic software, graphic computers, graphic applications, and more. AVERAGE PRICE: $5.00 - $6.00
	MAGAZINE: PC Magazine E-MAIL ADDRESS: Unknown WEB PAGE: http://www.pcmag.com ABOUT MAGAZINE: Great magazine with information on computer hardware, reviews and computer innovations. AVERAGE PRICE: $5.00 - $6.00
	MAGAZINE: PC WORLD E-MAIL ADDRESS: Unknown WEB PAGE: http://www.pcworld.com ABOUT MAGAZINE: Features everything new in the computer industry, computer questions and answers, reviews, and much more. PC World is one of the most well known computer magazines in the United States. AVERAGE PRICE: $5.00 - $6.00

S

MAGAZINE: Smart Business E-MAIL ADDRESS: Unknown WEB PAGE: http://www.zdnet.com/smartbusinessmag ABOUT MAGAZINE: Formerly PC Computing, Smart Business takes a new look at computers and the business aspects of computers and computer software. AVERAGE PRICE: $5.00 - $6.00

T

MAGAZINE: The Net E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Magazine that tells you all you need to know about the web, tells you the best web pages, and downloads all of the new events happening on the web. This magazine is no longer published. To order back orders of this magazine, call 1-888-4IMAGINE. The magazine has migrated into a new magazine, Business 2.0 AVERAGE PRICE: $No longer available

V

MAGAZINE: Visual Basic E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: For Visual Basic 3,4,5, and 6 programmers; explains all you need to know about Visual basic. Also has programs which other programmers have made that you can purchase. Also gives all the secrets which you need to know. AVERAGE PRICE: $No longer available

W

	MAGAZINE: Windows Magazine E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT THE MAGAZINE: The magazine for Windows 95, Windows 98, and Windows NT; with information on upgrading, customizing, and hot lists. AVERAGE PRICE: $No longer available
	MAGAZINE: Windows Pro E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT THE MAGAZINE: Complete information about Windows, Windows NT and information about Windows products and support. AVERAGE PRICE: $No longer available
	MAGAZINE: Windows Sources E-MAIL ADDRESS: Unknown WEB PAGE: N/A ABOUT THE MAGAZINE: The magazine for Windows 95 and Windows NT, giving you help with various topics, giving you new product information and more. AVERAGE PRICE: $No longer available
	MAGAZINE: WIRED E-MAIL ADDRESS: Unknown WEB PAGE: http://www.wired.com ABOUT MAGAZINE: Fun / BRIGHT magazine that gives you all the latest fun and informative information on computer technologies. AVERAGE PRICE: $5.00 - $6.00

Y

MAGAZINE: Yahoo Internet Life E-MAIL ADDRESS: N/A WEB PAGE: N/A ABOUT MAGAZINE: Yahoo, one of the largest most popular Internet sites and search engine, helps bring the Yahoo Internet Life magazine together by providing large amounts of Internet information and statistics to computer users. AVERAGE PRICE: $No longer available

Missing NTLDR

NTLDR is Missing

Press any key to restart

Boot: Couldn't find NTLDR
Please insert another disk

NTLDR is missing
Press Ctrl Alt Del to Restart

Cause:

1. Computer is booting from a non-bootable source.
2. Computer hard disk drive is not properly setup in BIOS.
3. Corrupt NTLDR and/or NTDETECT.COM file.
4. Misconfiguration with the boot.ini file.
5. Attempting to upgrade from a Windows 95, 98, or ME computer that is using FAT32.
6. New hard disk drive being added.
7. Corrupt boot sector / master boot record.
8. Seriously corrupted version of Windows 2000 or Windows XP.
9. Loose or Faulty IDE/EIDE hard disk drive cable.

Computer is booting from a non-bootable source

Many times this error is caused when the computer is attempting to boot from a non-bootable floppy disk or CD-ROM. First verify that no floppy diskette is in the computer, unless you are attempting to boot from a diskette.

If you are attempting to boot from a floppy diskette and are receiving this error message it is likely that the diskette does not have all the necessary files and/or is corrupt.

If you are attempting to install Windows XP or Windows 2000 and are receiving this error message as the computer is booting verify that your computer BIOS has the proper boot settings. For example, if you are attempting to run the install from the CD-ROM make sure the CD-ROM is the first boot device, and not the hard disk drive.

Second, when the computer is booting you should receive the below prompt.

Press any key to boot from the CD

Important: When you see this message press any key such as the Enter key immediately, otherwise it will try booting from the hard drive and likely get the NTLDR error again.

Note: If you are not receiving the above message and your BIOS boot options are set properly it's also possible that your CD-ROM drive may not be booting from the CD-ROM properly. Verify the jumpers are set properly on the CD-ROM drive. Additional information about checking the CD-ROM drive connections can be found on document CH000213.

Additional information: This error has also been known to occur when a memory stick is in a card reader and the computer is attempting to boot from it. If you have any type of card reader or flash reader make sure that no memory stick is inside the computer.

Computer hard disk drive is not properly setup in BIOS

Verify that your computer hard disk drive is properly setup in the BIOS / CMOS setup. Improper settings can cause this error. Additional information on how to enter the BIOS / CMOS setup can be found in document CH000192.

Corrupt NTLDR and/or NTDETECT.COM file

Windows 2000 users
Windows XP users

Windows 2000 users

If your computer is using Microsoft Windows 2000 and you are encountering the NTLDR error. Create the below boot.ini file on the floppy diskette drive.

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Microsoft Windows 2000 Professional" /fastdetect

Copy the NTLDR and NTDETECT.COM files from another computer using the same Operating System. Both of these files are located in the root directory of the primary hard disk drive. For example, C:\NTLDR and C:\NTDETECT.COM should be the locations of these files on many computers.

• Please keep in mind that these files are hidden system files, if you need additional help with viewing hidden files in Windows please see document CH000516.

Once these files have been copied to a floppy diskette reboot the computer and copy the NTLDR and NTDETECT.COM files to the root directory of the primary hard disk drive. Below is an example of what commonly should be performed from the A:\> drive.

copy ntldr c:
copy ntdetect.com c:

After the above two files have been copied, remove the floppy diskette and reboot the computer.

Windows XP users

1. Insert the Windows XP bootable CD into the computer.
2. When prompted to press any key to boot from the CD, press any key.
3. Once in the Windows XP setup menu press the "R" key to repair Windows.
4. Log into your Windows installation by pressing the "1" key and pressing enter.
5. You will then be prompted for your administrator password, enter that password.
6. Copy the below two files to the root directory of the primary hard disk. In the below example we are copying these files from the CD-ROM drive letter "E". This letter may be different on your computer.
   
   copy e:\i386\ntldr c:\
   copy e:\i386\ntdetect.com c:\
   
   
7. Once both of these files have been successfully copied, remove the CD from the computer and reboot.

Misconfiguration with the boot.ini file

Edit the boot.ini on the root directory of the hard disk drive and verify that it is pointing to the correct location of your Windows Operating System and that the partitions are properly defined. Additional information about the boot.ini can be found on document CH000492.

Attempting to upgrade from a Windows 95, 98, or ME computer that is using FAT32

If you are getting this error message while you are attempting to upgrade to Windows 2000 or Windows XP from Windows 95, Windows 98, or Windows ME running FAT32 please try the below recommendations.

1. Boot the computer with a Windows 95, Windows 98 or Windows ME bootable diskette.
2. At the A:\> prompt type:
   
   sys c:
   
   
3. After pressing enter you should receive the "System Transferred" message. Once this has been completed remove the floppy diskette and reboot the computer.

New hard disk drive being added

If you are attempting to add a new hard disk drive to the computer make sure that drive is a blank drive. Adding a new hard disk drive to a computer that already has Windows installed on it may cause the NTLDR error to occur.

If you are unsure if the new drive is blank or not try booting from a bootable diskette and format the new hard disk drive.

Corrupt boot sector / master boot record

It's possible your computer's hard disk drive may have a corrupt boot sector and/or master boot record. These can be repaired through the Microsoft Windows Recovery console by running the fixboot and fixmbr commands.

Additional information and help in getting into the Microsoft Windows Recovery console can be found on document CH000627.

Seriously corrupted version of Windows 2000 or Windows XP

If you have tried each of the above recommendations that apply to your situation and you continue to experience this issue it is possible you may have a seriously corrupted version of Microsoft Windows. Therefore we would recommend you reinstall Microsoft Windows 2000 and Windows XP.

If you are encountering this issue during your setup you may wish to completely erase your computer hard disk drive and all of its existing data and then install Microsoft Windows 2000 / Windows XP. Additional information about erasing the computer and starting over can be found on document CH000186.

Loose or Faulty IDE/EIDE hard disk drive cable

This issue has been known to be caused by a loose or fault IDE/EIDE cable. If the above recommendation does not resolve your issue and your computer hard disk drive is using an IDE or EIDE interface. Verify the computer hard disk drive cable is firmly connected by disconnected and reconnecting the cable.

If the issue continues it is also a possibility that the computer has a faulty cable, try replacing the hard disk drive cable with another cable and/or a new cable.