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By DEFAULT, your SHELL directs standard OUTPUT to your SCREEN or display.

By default, your shell directs standard output to your screen or display.

This COMMAND USES the X switch to extract a FILE. Here the file memo.ben will be restored from the tarfile MyBackup.tar.

This command uses the x switch to extract a file. Here the file memo.ben will be restored from the tarfile MyBackup.tar.

You can USE the z modifier with tar to COMPRESS your ARCHIVE at the same time as creating it.

You can use the z modifier with tar to compress your archive at the same time as creating it.

The SPLIT text filter will divide files into EQUALLY sized pieces. The DEFAULT length of each PIECE is 1,000 LINES.

The split text filter will divide files into equally sized pieces. The default length of each piece is 1,000 lines.

The repquota COMMAND is used to get a report on the status of the quotas you have SET including the AMOUNT of ALLOCATED SPACE and amount of used space.

The repquota command is used to get a report on the status of the quotas you have set including the amount of allocated space and amount of used space.

The pwconv COMMAND creates the FILE /etc/shadow and changes all PASSWORDS to 'X' in the /etc/passwd file.

The pwconv command creates the file /etc/shadow and changes all passwords to 'x' in the /etc/passwd file.

gpasswd -R
The gpasswd command is USED to change the PASSWORD ASSIGNED to a GROUP. Use the -r option to remove the password from the group.

gpasswd -r
The gpasswd command is used to change the password assigned to a group. Use the -r option to remove the password from the group.

ctrl-z
USING ctrl-z will SUSPEND a JOB and PUT it in the BACKGROUND.

ctrl-z
Using ctrl-z will suspend a job and put it in the background.

logrotate
The logrotate COMMAND can be USED to AUTOMATE the rotation of VARIOUS logs.

logrotate
The logrotate command can be used to automate the rotation of various logs.

/var/LOG/messages
By DEFAULT, the MAIN SYSTEM log is /var/log/messages.

/var/log/messages
By default, the main system log is /var/log/messages.

2
Linux can be INSTALLED on two PARTITIONS, ONE as / which will CONTAIN all files and a swap PARTITION.

2
Linux can be installed on two partitions, one as / which will contain all files and a swap partition.

dmesg
The dmesg command displays the SYSTEM messages CONTAINED in the kernel RING buffer.
By USING this command immediately after BOOTING your computer, you will see the boot messages.

dmesg
The dmesg command displays the system messages contained in the kernel ring buffer.
By using this command immediately after booting your computer, you will see the boot messages.

The SYS user owns the DATA dictionary. The SYS and SYSTEM users are created when the database is created.

The SYS user owns the data dictionary. The SYS and SYSTEM users are created when the database is created.

TOP-The top utility shows a LISTING of all running PROCESSES that is DYNAMICALLY UPDATED.

Top-The top utility shows a listing of all running processes that is dynamically updated.

To the screen or DISPLAY-By DEFAULT, your shell DIRECTS STANDARD output to your screen or display.

To the screen or display-By default, your shell directs standard output to your screen or display.

Syslogd-The syslogd daemon is responsible for TRACKING system INFORMATION and saving it to SPECIFIED LOG FLIES.

Syslogd-The syslogd daemon is responsible for tracking system information and saving it to specified log flies.

root-Whenever you install Linux, only ONE USER account is created. This is the SUPER user account ALSO known as root.

root-Whenever you install Linux, only one user account is created. This is the super user account also known as root.

kernel.h-To DETERMINE the various levels of messages that are DEFINED on your SYSTEM, examine the kernel.h FILE.

kernel.h-To determine the various levels of messages that are defined on your system, examine the kernel.h file.

FSCK-The fsck COMMAND is used to CHECK the INTEGRITY of the file SYSTEM on your disk.

fsck-The fsck command is used to check the integrity of the file system on your disk.

fc -5-The fc COMMAND can be USED to EDIT or rerun commands you have PREVIOUSLY entered. To SPECIFY the number of commands to list, use -n.

fc -5-The fc command can be used to edit or rerun commands you have previously entered. To specify the number of commands to list, use -n.

ECHO $SHELL-The name and path to the shell you are using is saved to the SHELL ENVIRONMENT variable. You can then use the echo command to PRINT out the VALUE of any variable by PRECEDING the variable’s name with $. Therefore, typing echo $SHELL will display the name of your shell.

echo $SHELL-The name and path to the shell you are using is saved to the SHELL environment variable. You can then use the echo command to print out the value of any variable by preceding the variable’s name with $. Therefore, typing echo $SHELL will display the name of your shell.

cylinders-When CREATING a NEW partition you MUST first specify its starting cylinder. You can then EITHER specify its size or the ENDING cylinder.

cylinders-When creating a new partition you must first specify its starting cylinder. You can then either specify its size or the ending cylinder.

command-The last field, CALLED EITHER command or login command, is used to SPECIFY what SHELL the user will use when he logs in.

command-The last field, called either command or login command, is used to specify what shell the user will use when he logs in.

Swap SPACE is used as an extension of PHYSICAL RAM, the more RAM you have, the LESS swap space is required. You can add the amount of swap space and the amount of RAM together to get the amount of RAM Linux will use. For example, if you have 8MB of RAM on your machine’s motherboard, and a 16MB swap-space PARTITION, Linux will behave as though you had 24MB of total RAM.

Swap space is used as an extension of physical RAM, the more RAM you have, the less swap space is required. You can add the amount of swap space and the amount of RAM together to get the amount of RAM Linux will use. For example, if you have 8MB of RAM on your machine’s motherboard, and a 16MB swap-space partition, Linux will behave as though you had 24MB of total RAM.

The root LOGIN does not RESTRICT you in any way. When you log in as root, you become the system. The root login is also sometimes called the super user login. With ONE SIMPLE command, issued either on purpose or by accident, you can destroy your entire Linux installation. For this reason, use the root login only when necessary. Avoid experimenting with commands when you do log in as root.

The root login does not restrict you in any way. When you log in as root, you become the system. The root login is also sometimes called the super user login. With one simple command, issued either on purpose or by accident, you can destroy your entire Linux installation. For this reason, use the root login only when necessary. Avoid experimenting with commands when you do log in as root.

The write command enables you to write an actual message on the other terminal online. You have to issue the write command with the login ID of the user with whom you want to communicate. The write command informs the user at the other end that there is a message from another user. write pastes that message onto the other user’s terminal if their terminal’s write permissions are SET. Even if they are in the middle of an edit session, write overwrites WHATEVER is on the SCREEN. The edit session contents are not CORRUPTED; you can restore the original screen on most editors with Ctrl-L. write is mostly used for one-way communication, but you can have an actual conversation as well.

The write command enables you to write an actual message on the other terminal online. You have to issue the write command with the login ID of the user with whom you want to communicate. The write command informs the user at the other end that there is a message from another user. write pastes that message onto the other user’s terminal if their terminal’s write permissions are set. Even if they are in the middle of an edit session, write overwrites whatever is on the screen. The edit session contents are not corrupted; you can restore the original screen on most editors with Ctrl-L. write is mostly used for one-way communication, but you can have an actual conversation as well.

The major advantage of a hash table is its speed. Because the hash FUNCTION is to take a range of KEY values and TRANSFORM them into index values in such a way that the key values are distributed randomly ACROSS all the indices of a hash table.

The major advantage of a hash table is its speed. Because the hash function is to take a range of key values and transform them into index values in such a way that the key values are distributed randomly across all the indices of a hash table.

We can use TWO major techniques to handle the collisions. They are open addressing and separate CHAINING. In open addressing, data items that hash to a full array cell are placed in another cell in the array. In separate chaining, each array element CONSISTS of a LINKED list. All data items hashing to a given array INDEX are inserted in that list.

We can use two major techniques to handle the collisions. They are open addressing and separate chaining. In open addressing, data items that hash to a full array cell are placed in another cell in the array. In separate chaining, each array element consists of a linked list. All data items hashing to a given array index are inserted in that list.

The file SERVER is a MACHINE that shares its DISK storage and FILES with other machines on the network.

The file server is a machine that shares its disk storage and files with other machines on the network.

NFS stands for Network File SYSTEM. NFS enables filesystems PHYSICALLY residing on one computer system to be used by other computers in the network, appearing to USERS on the remote HOST as just ANOTHER local disk.

NFS stands for Network File System. NFS enables filesystems physically residing on one computer system to be used by other computers in the network, appearing to users on the remote host as just another local disk.

Dynamic addressing simplifies network administration because the s/w keeps TRACK of IP addresses rather than requiring an administrator to manage the task. That MEANS new COMPUTER can be ADDED to the network without any risk of manually assigning unique IP ADDRESS.

Dynamic addressing simplifies network administration because the s/w keeps track of IP addresses rather than requiring an administrator to manage the task. That means new computer can be added to the network without any risk of manually assigning unique IP address.

The tail UTILITY displays the end of a file. The -15 tells tail to DISPLAY the last FIFTEEN LINES of each specified file.

The tail utility displays the end of a file. The -15 tells tail to display the last fifteen lines of each specified file.

The tac TEXT filter is a reverse cat. It DISPLAYS a file STARTING with the last line and ENDING with the first line.

The tac text filter is a reverse cat. It displays a file starting with the last line and ending with the first line.

The default PAGE length when USING pr is 66 lines. The -l OPTION is USED to specify a different length.

The default page length when using pr is 66 lines. The -l option is used to specify a different length.

The paste TEXT filter USUALLY joins two files separating the corresponding lines with a tab. The -s option, however, will cause paste to DISPLAY the FIRST file, DOG, then a new line character, and then the file cat.

The paste text filter usually joins two files separating the corresponding lines with a tab. The -s option, however, will cause paste to display the first file, dog, then a new line character, and then the file cat.

The OD TEXT filter will dumpt the contents of a file and display it in 2-byte OCTAL NUMBERS.

The od text filter will dumpt the contents of a file and display it in 2-byte octal numbers.

If the number of lines to DISPLAY is not specified, the first ten lines of the specified file are displayed. The asterick tells HEAD to display the content of each file in the present working directory.

If the number of lines to display is not specified, the first ten lines of the specified file are displayed. The asterick tells head to display the content of each file in the present working directory.

By default, EXPAND converts tabs to EIGHT spaces. Use the -t option to change this behavior.

By default, expand converts tabs to eight spaces. Use the -t option to change this behavior.

When using sed to do a search and REPLACE, its default action is to only replace the first occurrence in each LINE. Adding the ‘G’ makes sed replace all occurrences of the search TERM even when it occurs multiple TIMES on the same line.

When using sed to do a search and replace, its default action is to only replace the first occurrence in each line. Adding the ‘g’ makes sed replace all occurrences of the search term even when it occurs multiple times on the same line.

The DIGITS of your UMASK represent owner, GROUP and others in that order.
The 0 gives read and WRITE for files and the 2 gives read only for files.

The digits of your umask represent owner, group and others in that order.
The 0 gives read and write for files and the 2 gives read only for files.

When the STICKY BIT is set on a WORLD writable directory, only the OWNER can delete any file contained in that directory.

When the sticky bit is set on a world writable directory, only the owner can delete any file contained in that directory.

Because the LINK in BOB’s DIRECTORY is a symbolic link, if the file sales data in the /data directory is DELETED, the symbolic link will no LONGER work.

Because the link in bob’s directory is a symbolic link, if the file sales data in the /data directory is deleted, the symbolic link will no longer work.

By creating a link to the file in each user’s home directory, each user is able to easily open and edit the spreadsheet. Also, any changes that are made are SEEN by all the USERS with ACCESS.

By creating a link to the file in each user’s home directory, each user is able to easily open and edit the spreadsheet. Also, any changes that are made are seen by all the users with access.

The repquota COMMAND is used to get a REPORT on the status of the QUOTAS you have SET including the AMOUNT of allocated space and amount of used space.

The repquota command is used to get a report on the status of the quotas you have set including the amount of allocated space and amount of used space.

Quotas are set on a partition by partition BASIS. If your users have home DIRECTORIES on different PARTITIONS, you will need to CONFIGURE quotas for each partition.

Quotas are set on a partition by partition basis. If your users have home directories on different partitions, you will need to configure quotas for each partition.

If you do not UNMOUNT the FLOPPY before REMOVING it, the files on the floppy may become corrupted.

If you do not unmount the floppy before removing it, the files on the floppy may become corrupted.

The .Z extension INDICATES that this is a file that has been compressed USING the compress utility. The zcat utility PROVIDES the ability to display the CONTENTS of a compressed file.

The .Z extension indicates that this is a file that has been compressed using the compress utility. The zcat utility provides the ability to display the contents of a compressed file.

The -n OPTION when used with sed prints only the LINES CONTAINING the pattern. In this CASE, the pattern is ‘BOB’ and the file to be searched is kickoff.

The -n option when used with sed prints only the lines containing the pattern. In this case, the pattern is ‘Bob’ and the file to be searched is kickoff.

Using the -c OPTION with the GREP COMMAND will show the total number of LINES containing the specified pattern rather than DISPLAYING the lines containing the pattern.

Using the -c option with the grep command will show the total number of lines containing the specified pattern rather than displaying the lines containing the pattern.

Use the asterick (*) to match to zero or more CHARACTERS. The ‘$‘ matches to any one CHARACTER so SALE$ would not find sale.

Use the asterick (*) to match to zero or more characters. The ‘$‘ matches to any one character so sale$ would not find sale.