What is Permissions?
"Every file or folder in Linux has access permissions. There are three types of permissions "
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Read access
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Write access
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Execute access
For File :--
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Read access :-- Permission to read a file
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Write access :-- Permission to write to a file
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Execute access :-- Permission to execute a program
For Directory :--
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Read access :-- Permission to list a directory's contents
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Write access :-- Permission to create and remove files from a directory.
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Execute access :-- Permission to change in to a directory and do a long listing of the directory.
Change file ownership :--
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#chown for file
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#chown -R for directory
Change Permissions –
Symbolic method :--
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#chmod -R <mode> <file>
Mode
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u,g,o for user, group, other
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+ or - for grant or deny.
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r,w,x for read, write and execute.
Example:--
#chmod -R ugo +rwx <file name>
Numeric Method :--
Uses a three digit mode number.
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First digit specifies owner's permission
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Second digit specifies group permission
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third digit specifies other's permission
Permission are calculated by adding
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4 (for read)
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2 (for write)
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1 (for execute)
Example
chmod 640 <file name>
