Documentation for chmod

chmod.md

chmod

Change the permission of a file or directory

• Syntax

chmod {{who}} {{operation}} {{perm}} {{file}}

{{who}} is any combination of u (user), g (group), o (owner) or a (all)

{{operation}} is either + (giving permission) or - (removing permission)

{{perm}} is any combination of r (read), w (write), x (execute)

• Give the user rights to execute a file/directory

chmod u+x {{file}}

• Gives the user, group and owner rights to execute and read

chmod ugo+xr {{file}}

• Removes executable rights from group

chmod g-x {{file}}

• Use comma to separate the multiple permission sets

chmod u+r,g+x filename

• Assign the permission recursively to directory

chmod -R u+x /path/to/directory/

Alternatively 3-digit number can be used to encode given permissions. Each digit represents permissions for (u)ser, (g)roup and (o)thers. Each digit is an octal number, bits give you permission to execute (bit 0), write (bit 1) and read (bit 2).

User    Group   Others
r w x   r w x   r w x
4 2 1   4 2 1   4 2 1

• Give full permission to file owner, group and others can read and execute file

chmod 777 {{file}}

I think this is better then what I wrote.