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Linux - Set file permissions using symbolic
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so into our previous video we have
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discussed that chmod uses two type of
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permission settings very first we can
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set or change the permissions by using a
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symbolic method that we are going to see
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over here so if I'm using a symbolic
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method for changing the permission I'll
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be using some characters though this
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particular characters are this
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particular operators we shall be using
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we can be used with chmod command where
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I'll be using one that is my plus symbol
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for adding affirmation to a file
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now for example I want to add execute
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permission so I'm just giving the plus X
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if I want to add a write permission I'll
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be using plus R or if I want to add an
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read permission I will be using plus R
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here we have subtract formation subtract
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symbol will be used for removing a
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certain formation like if already I have
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some read/write/execute for my group if
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I want to remove it I'll be using minus
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R for everything if I want to remove
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only write permission from it I'll be
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using minus W that means you are just
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removing a write formation if I want
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remove a read permission I'll be using -
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are so same way we have is equals to
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equals the sign is for replacing the
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complete formation now as we have seen
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like plus and minus can be used for
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adding or removing the formation but
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what if I want to change the complete
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formation at a time
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in spite of adding or removing it I can
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directly use equals to symbol for
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changing the complete permissions at
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time so let us see into the terminal how
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we can use the symbolic method for
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change in the formation of a file into
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our Linux Shawn dekstop we have multiple
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files and we can give a I'll come on to
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check the formations of the files and
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directory now as discussed you can see
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there is a first bit when I've created a
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firm they're showing me - come on even
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if I create a new file
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it will show me - in front of the
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filename right
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that means this is of a but if I create
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a directory now if I am creating to
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create a directory with folder - and
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rest check the directory has be in front
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of it right that means the first bit is
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clear - means of a B means a directory
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now we are going to talk about
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deformations so as discussed we have the
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groups of three of the spits so three
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bits group we will have for the owner
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permission three bits group we will have
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deformation for the group
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while the three bits will be assigned
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for the others so basically the sequence
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is fixed first free then right then
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execute if you do not have execute it
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will remain blank that means it will be
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a -
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so here in document one we have
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readwrite formation to affirm that means
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the trainer this is the owner of the
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directory has only read and write
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permission no execute now if I want to
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use or if I want to add execute
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permission using a symbolic way I'll be
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using in such a way chmod now here you
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means owner Njemanze group and omens
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others
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now give CH more you I want to add so
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plus sign execute permissions or X so
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I'm going to add owner and execute
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permission for a file called as document
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one let us check whether this change has
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been done or not again check we have
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added it right so now if suppose I want
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to the write permission from here
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execute has already been removed so if I
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want to just remove the write permission
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so I just want to define my group that
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they can only read the content of home
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file so I can give CH more G that is for
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group - for removing a permission and
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here I'm going to remove the write
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formation from the same file document 1
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and just have a look we have just
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removed the write permission from here
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right so it access only read and other
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two are like that means if the group has
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only read permission now same way we can
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also set permissions for others now for
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others if I suppose I want to define
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read and execute formation so again I'll
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be giving the same command chmod or for
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others I want to add execute formation
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for the same file document one let us
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have a list and you can see if we have
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just started the execute permission now
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if I want to keep the all the
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permissions together now for example I
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want to remove write permission from the
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owner
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and I want to add execute permission to
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the group simultaneously
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I'll give the command chmod u minus W so
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I'm going to remove the write permission
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from the owner basically we don't do but
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here I am doing for showing the
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practical then into the group we are
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going to add the execute permission
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right so plus X and for other see I
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don't want to make any changes to leave
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it as this and to the file called as
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document one let us check the changes it
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happened now the owner has written
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execute group has written execute while
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we haven't made any changes into the
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document though we have read an execute
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now same way if I want to remove this
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both read and execute from the others
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let us check again we have read an
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execute I want to remove both read and
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execute at a time from the others I will
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be giving me come on CH more o minus R
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minus X from or minor are my egg ads
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from document one just give and check
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there is no permission to my document
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one for the other users who are not into
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my group as well as who is not owner
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right so this is where how we can change
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the directory permissions by using plus
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and minus signs now also we have an
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operator called as equals two we can
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also use equals two to replace the
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content of a file now for example I want
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my user permission to set as read write
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execute group formation as read and
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execute so without looking to your
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existing permission we can replace the
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permission completely and for others I
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want to set only read permission for the
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same firm document one and rest check
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it's changed read write execute for the
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owner read and execute for the group
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while others has
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only read formation so this is how to
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leave is a deformation using the
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parameters and one more we can see if
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suppose I want to set three your owner
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group and others the same formation so
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we can also use chmod II a means all all
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means user group and others I want to
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set all read write and execute formation
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that to I want to give full control to
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everyone so I will giving the command
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document one just let us have a look on
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this particular document I can see read
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and execute for owner read and execute
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for your crop and again read and execute
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for the others so simultaneously we can
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check the same permission to all three
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groups so this is how we have seen how
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we can use the symbolic method to change
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the formation of the you know document
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or a particular directory we have
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created now into next video we are going
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to see how we can do it by using the
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octal way
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