Ubuntu – Understanding chmod Symbolic Notation and use of Octal

chmodcommand linepermissions

Many new users make mistakes (or have misunderstanding) while applying chmod on files or directories, because of a lack of informative knowledge of:

  • Symbolic notation for ugo and rwx
  • Use of octal numbers

So, in this answer I have provided some useful information that can help to understand correct symbolic notation and using octal numbers.

Best Answer

Informative knowledge is provided with the help of The Linux Command-line as refrence/source.

  • First of all it is very essential to know about ugo and rwx manner:

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  • Understanding of attribute which can be out put by ls-l:

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  • Applying Permission:

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  • Using Octal number:

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Hence Following work same like:

chmod +rwx [file_name]
chmod 777 [file_name]


chmod 775 [file_name]
chmod ug+rwx,o=rx [file_name]

Hope this helps new users to understand and get knowledge about Symbolic Notation & using Octal number for chmod.

you can download pdf version of linux-command-line book from sourceforge-project

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