Chapter 4 Study Guide - Revision history

Ziggybsm: /* Special Permissions */

2012-02-10T03:05:30Z

Special Permissions

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	[[File:special permissions.jpg]]		[[File:special permissions.jpg]]


			'''Example of setting Sticky Bit in special permissions'''

	{root@server1 ~} # ls -l		{root@server1 ~} # ls -l

Ziggybsm: /* Special Permissions */

2012-02-10T03:00:55Z

Special Permissions

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	'''Sticky Bit'''		'''Sticky Bit'''
	Prevents users who have permission to write to a directory from deleting files they did not create.		Prevents users who have permission to write to a directory from deleting files they did not create.


	[[File:special permissions.jpg]]		[[File:special permissions.jpg]]

	{root@server1 ~} # ls -l		{root@server1 ~} # ls -l

Ziggybsm: /* Special Permissions */

2012-02-10T02:51:47Z

Special Permissions

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	Prevents users who have permission to write to a directory from deleting files they did not create.		Prevents users who have permission to write to a directory from deleting files they did not create.

			[[File:special permissions.jpg]]
	{root@server1 ~} # ls -l		{root@server1 ~} # ls -l

Ziggybsm: /* Special Permissions */

2012-02-10T02:47:56Z

Special Permissions

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	'''SUID'''		'''SUID'''
	Gives user who executes file temporarily ownership of a file while executing.		Gives user who executes file temporarily ownership of a file while executing.

	'''SGID'''		'''SGID'''
	Gives regular user who executes the file or binary compiled program temporary membership of the group that is attached to it.		Gives regular user who executes the file or binary compiled program temporary membership of the group that is attached to it.

	'''Sticky Bit'''		'''Sticky Bit'''
	Prevents users who have permission to write to a directory from deleting files they did not create.		Prevents users who have permission to write to a directory from deleting files they did not create.

Ziggybsm: /* Special Permissions */

2012-02-10T02:47:03Z

Special Permissions

← Older revision		Revision as of 02:47, 10 February 2012
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	{root@server1 ~} # ls -l		{root@server1 ~} # ls -l

	total 12		total 12

	drwx------ 2 root root 4096 May 2 21:41 dir2		drwx------ 2 root root 4096 May 2 21:41 dir2

	{root@server1 ~} # chmod 1770 dir2		{root@server1 ~} # chmod 1770 dir2

	{root@server1 ~} ls –l		{root@server1 ~} ls –l

	total 12		total 12

	drwxrwx--T 2 root root 4096 May 2 21:41 dir2		drwxrwx--T 2 root root 4096 May 2 21:41 dir2

Ziggybsm at 02:44, 10 February 2012

2012-02-10T02:44:33Z

← Older revision		Revision as of 02:44, 10 February 2012
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	==Special Permissions==		==Special Permissions==

			'''SUID'''
			Gives user who executes file temporarily ownership of a file while executing.
			'''SGID'''
			Gives regular user who executes the file or binary compiled program temporary membership of the group that is attached to it.
			'''Sticky Bit'''
			Prevents users who have permission to write to a directory from deleting files they did not create.


			{root@server1 ~} # ls -l
			total 12
			drwx------ 2 root root 4096 May 2 21:41 dir2
			{root@server1 ~} # chmod 1770 dir2
			{root@server1 ~} ls –l
			total 12
			drwxrwx--T 2 root root 4096 May 2 21:41 dir2

Ziggybsm at 02:41, 10 February 2012

2012-02-10T02:41:59Z

← Older revision		Revision as of 02:41, 10 February 2012
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			==Filesystem Hierarchy Standard==

			*Defines a standard set of directories, their subdirectories and file content used by Linux and UNIX
			*Allows a user proficient with Linux t navigate UNIX easier.
			*Gives software developers to locate files on different distributions of Linux
			*Allows creation of software that is not distribution specific


	==Finding Files==		==Finding Files==

Ziggybsm at 02:21, 10 February 2012

2012-02-10T02:21:35Z

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	New directories are given rwxrwxrwx by the system when they are created.		New directories are given rwxrwxrwx by the system when they are created.

	~~'''~~Special Permissions~~'''~~		==Special Permissions==

Ziggybsm at 02:20, 10 February 2012

2012-02-10T02:20:30Z

← Older revision		Revision as of 02:20, 10 February 2012
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	New directories are given rwxrwxrwx by the system when they are created.		New directories are given rwxrwxrwx by the system when they are created.

			'''Special Permissions'''

Splm19 at 22:57, 9 February 2012

2012-02-09T22:57:06Z

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	[root@server1 -] #		[root@server1 -] #

			==Interpreting File Permissions==

			All files contain information regarding permissions in the “mode”
			Mode is broken into three sections based on the users who receive the permissions

			User (owner) permissions

			Group (group owner) permissions

			Other (everyone else) permissions

			Each of the users can be assigned different permissions

			Read – allows user to open and read file

			- allows user to list contents of directory (if given execute permission)

			Write – allows user to open, read, and edit file

			- allows user to add or remove files to and from directory (if given execute)

			Execute – allows user to execute the file in memory

			- allows user to enter directory and work with contents

			==Changing File Permissions==

			There are two different methods for changing file permissions

			Symbolic

			Numeric

			Uses the “chmod” command to change permissions

			The chmod command takes two arguments at minimum

			The first argument specifies the criteria to change permissions
			The remaining arguments indicate the filename to change

			'''Symbolic Method'''

			You must first determine user to apply permissions to

			U (user)

			G (group)

			O (other)

			A (all categories)

			Permissions can be added, subtracted, or specify exact permissions

			+ adds permissions

			- subtracts permissions

			= defines exact permissions

			Uses three permission levels

			R (read)

			W (write)

			X (execute)

			When typing the users, they are separated by commas. Also ensure that there are no spaces between any criteria.

			ex

			#chmod u+r,g+r,o+r file1

			#chmod u-wr file1

			'''Numeric Method'''

			Uses binary powers of two to determine permissions

			Each user category assigned permissions of 0-7

			R(read) = 4

			W(write)=2

			X(execute=1

			None = 0

			Add the values of desired permissions to determine the number to input

			ex.

			#chmod 540 file1

			User has read and execute, group has read, other has none


	==Understand and Create linked files==		==Understand and Create linked files==