find: Numeric Modes

1 
1 5.3 Numeric Modes
1 =================
1 
1 As an alternative to giving a symbolic mode, you can give an octal (base
1 8) number that represents the new mode.  This number is always
1 interpreted in octal; you do not have to add a leading 0, as you do in
1 C. Mode 0055 is the same as mode 55.
1 
1    A numeric mode is usually shorter than the corresponding symbolic
1 mode, but it is limited in that it cannot take into account a file's
1 previous permissions; it can only set them absolutely.
1 
1    The permissions granted to the user, to other users in the file's
1 group, and to other users not in the file's group each require three
1 bits, which are represented as one octal digit.  The three special
1 permissions also require one bit each, and they are as a group
1 represented as another octal digit.  Here is how the bits are arranged,
1 starting with the lowest valued bit:
1 
1      Value in  Corresponding
1      Mode      Permission
1 
1                Other users not in the file's group:
1         1      Execute
1         2      Write
1         4      Read
1 
1                Other users in the file's group:
1        10      Execute
1        20      Write
1        40      Read
1 
1                The file's owner:
1       100      Execute
1       200      Write
1       400      Read
1 
1                Special permissions:
1      1000      Restricted deletion flag or sticky bit
1      2000      Set group ID on execution
1      4000      Set user ID on execution
1 
1    For example, numeric mode 4755 corresponds to symbolic mode
1 'u=rwxs,go=rx', and numeric mode 664 corresponds to symbolic mode
1 'ug=rw,o=r'.  Numeric mode 0 corresponds to symbolic mode 'a='.
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